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Sample records for left atrium pla

  1. UFO in the Left Atrium: How to Capture Metal Debris Floating in the Left Atrium.

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    Fassini, Gaetano; Moltrasio, Massimo; Conti, Sergio; Biagioli, Viviana; Tondo, Claudio

    2016-06-01

    Electrophysiology procedures involving left atrium navigation are becoming more frequent, mostly due to the increase of atrial fibrillation ablation. Mapping catheters of different shapes and size as well as dedicated sheaths are mandatory tools for the accomplishment of procedural end point. Therefore, technical issues are expected, usually unrelated to significant risk. However, any accidental intra-atrial device loss of integrity implies a risk of cerebrovascular embolization. The lack of clear evidence on how to manage these events and the need for a quick solution complicate the scenario. We report an empirical solution in the case of debris floating in the left atrium. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  2. Left Atrium Papillary Fibroelastomas: A Cause of Cerebral Emboli

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    A. G. Ciss

    2012-01-01

    Full Text Available Papillary fibroelastomas are cardiac benign tumours. Among the benign cardiac tumor, papillary fibroelastomas are reported second after myxomas. Most often diagnosed incidentally, papillary fibroelastomas may embolize to cerebral circulation. Valvular locations are predominant; location in left atrium is rare. In this paper, we present a case of papillary fibroelastoma located in left atrium with symptoms of cerebral embolization. Transoesophageal echocardiography diagnosed a mobile mass. The patient was treated with surgical resection without further embolic complication.

  3. Giant left atrium encountered during right-sided thoracentesis

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    Rashmi Advani

    Full Text Available Giant left atrium is an uncommon pathology to encounter during bedside chest ultrasound, but is an important structure to be aware of when considering thoracentesis. This cardiac structure could easily be mistaken for loculated pleural fluid. This case also supports growing evidence that expert users can safely perform thoracentesis without completely reversing therapeutic anticoagulation. Keywords: Giant left atrium, Thoracentesis, Rheumatic heart disease, Ultrasound

  4. Anatomic relationship between left coronary artery and left atrium in patients undergoing atrial fibrillation ablation.

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    Anselmino, Matteo; Torri, Federica; Ferraris, Federico; Calò, Leonardo; Castagno, Davide; Gili, Sebastiano; Rovera, Chiara; Giustetto, Carla; Gaita, Fiorenzo

    2017-07-01

    Atrial fibrillation transcatheter ablation (TCA) is, within available atrial fibrillation rhythm control strategies, one of the most effective. To potentially improve ablation outcome in case of recurrent atrial fibrillation after a first procedure or in presence of structural myocardial disease, isolation of the pulmonary veins may be associated with extensive lesions within the left atrium. To avoid rare, but potentially life-threatening, complications, thorough knowledge and assessment of left atrium anatomy and its relation to structures in close proximity are, therefore, mandatory. Aim of the present study is to describe, by cardiac computed tomography, the anatomic relationship between aortic root, left coronary artery and left atrium in patients undergoing atrial fibrillation TCA. The cardiac computed tomography scan of 21 patients affected by atrial fibrillation was elaborated to segment left atrium, aortic root and left coronary artery from the surrounding structures and the following distances measured: left atrium and aortic root; left atrium roof and aortic root; left main coronary artery and left atrium; circumflex artery and left atrium appendage; and circumflex artery and mitral valve annulus. Above all, the median distance between left atrium and aortic root (1.9, 1.5-2.1 mm), and between circumflex artery and left atrium appendage ostium (3.0, 2.1-3.4 mm) were minimal (≤3 mm). None of measured distances significantly varied between patients presenting paroxysmal versus persistent atrial fibrillation. The anatomic relationship between left atrium and coronary arteries is extremely relevant when performing atrial fibrillation TCA by extensive lesions. Therefore, at least in the latter case, preablation imaging should be recommended to avoid rare, but potentially life-threatening, complications with the aim of an as well tolerated as possible procedure.

  5. Right superior vena cava draining into the left atrium

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    Calcagni, Giulio; Sidi, Daniel; Bonnet, Damien [University Rene Descartes-Paris 5, Department of Paediatric Cardiology, Hopital Necker-Enfants Malades, Paris (France); Batisse, Alain [Institut de Puericulture et de Perinatalogie, Paris (France); Vouhe, Pascal [University Rene Descartes-Paris 5, Department of Paediatric Cardiac Surgery, Hopital Necker-Enfants Malades, Paris (France); Ou, Phalla [University Rene Descartes-Paris 5, Department of Paediatric Cardiology, Hopital Necker-Enfants Malades, Paris (France); University Rene Descartes-Paris 5, Department of Pediatric Radiology, Hopital Necker-Enfants Malades, Paris (France)

    2008-08-15

    The right superior vena cava draining into the left atrium is a rare malformation causing cyanosis and clubbing in patients in whom no other signs of congenital heart defect are present. Diagnosis may be difficult as cyanosis may be mild and the anomaly is not always easily detectable by echocardiography. For this reason we report a 13-month-old male in whom we confirmed the clinical and echocardiographic suspicion of anomalous drainage of the right superior vena cava using multidetector CT. This allowed successful surgical reconnection of the right superior vena cava to the right atrium. (orig.)

  6. Right superior vena cava draining into the left atrium

    International Nuclear Information System (INIS)

    Calcagni, Giulio; Sidi, Daniel; Bonnet, Damien; Batisse, Alain; Vouhe, Pascal; Ou, Phalla

    2008-01-01

    The right superior vena cava draining into the left atrium is a rare malformation causing cyanosis and clubbing in patients in whom no other signs of congenital heart defect are present. Diagnosis may be difficult as cyanosis may be mild and the anomaly is not always easily detectable by echocardiography. For this reason we report a 13-month-old male in whom we confirmed the clinical and echocardiographic suspicion of anomalous drainage of the right superior vena cava using multidetector CT. This allowed successful surgical reconnection of the right superior vena cava to the right atrium. (orig.)

  7. VARIATION IN THE OPENINGS (OSTIA OF LEFT PULMONARY VEINS INTO THE LEFT ATRIUM: A CASE REPORT

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    Sesi

    2015-03-01

    Full Text Available During early embryonic development, absorption of pulmonary venous network by the left primitive atrial chamber results in opening of four pulmonary veins which drain independently into its chamber. The extent of absorption and hence, the number of pulmon ary veins which open into the left atrium, may vary. Here we report a variation in the opening of the Left upper (superior pulmonary vein into the Left atrium. A total of six openings observed

  8. LEFT ATRIUM THROMBOSIS IN PATIENTS WITH RHEUMATIC MITRAL VALVULAR DISEASE

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    N. D. Kaverin

    2012-01-01

    Full Text Available Systemic thromboembolism — fairly common complication of mitral valvular disease, often leading to disability or fatal consequences for the patient. The source of emboli in most cases, are blood clots localized in the left atrium. The survey reflected basic views on the pathogenesis, diagnosis, treatment and prevention of intraatrial thrombosis according to new scientific advances. Articles (reviews, meta-analyzes and original researchs from Pub Med database, as well as domestic literature were used.

  9. An elusive persistent left superior vena cava draining into left atrium

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    A. Soward; F.J. ten Cate (Folkert); P.M. Fioretti (Paolo); P.W.J.C. Serruys (Patrick); J.R.T.C. Roelandt (Jos)

    1986-01-01

    textabstractA case report of a persistent left superior vena cava draining into left atrium with a fibromuscular left ventricular outflow tract obstruction and a small atrial septal defect. The anomalous vessel escaped detection during two right and left heart catheterizations from the right arm and

  10. Anesthetic implications of total anomalous systemic venous connection to left atrium with left isomerism

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    Parimala Prasanna Simha

    2012-01-01

    Full Text Available Total anomalous systemic venous connection (TASVC to the left atrium (LA is a rare congenital anomaly. An 11-year-old girl presented with complaints of palpitations and cyanosis. TASVC with left isomerism and noncompaction of LV was diagnosed after contrast echocardiogram and computed tomography angiogram. The knowledge of anatomy and pathophysiology is essential for the successful management of these cases. Anesthetic concerns in this case were polycythemia, paradoxical embolism and rhythm abnormalities. The patient was successfully operated by rerouting the systemic venous connection to the right atrium.

  11. A region-specific quantitative profile of autonomic innervation of the canine left atrium and pulmonary veins.

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    Gao, Chong-han; Wang, Fei; Jiang, Rong; Zhang, Jin; Mou, Huamin; Yin, Yue-hui

    2011-07-05

    The aim of the present study was to determine and quantify the cardiac autonomic innervation of the canine atria and pulmonary vein. Tissue specimens were taken from the canine pulmonary veins (PVs), posterior left atrium (PLA), left atrial roof (LAR), anterior left atrium (ALA), interatrial septum (IAS), and left atrial appendage (LAA) respectively for immunohistochemical analysis and nerve density determination. Both sympathetic and parasympathetic nerve densities decreased in the order: PLA>PV>IAS>LAR>ALA>LAA. For sympathetic nerve, multiple comparisons between any two regions showed a significant difference (PIAS vs. LAR, and LAR vs. ALA; for parasympathetic nerve, all the differences between any pair of regions were statistically significant (PIAS vs. LAR, LAR vs. ALA, and ALA vs. LAA. For both nerve types, there was a decreasing gradient of nerve densities from the external to internal layer (P<0.001, for each comparisons). Nerve density at the ostia for either nerve type was significantly higher than at the distal segments of PVs (P<0.001). In summary, the LA and PVs are innervated by sympathetic and parasympathetic nerves in a regionally heterogeneous way, which may be important for the pathophysiological investigation and ablation therapy of atrial fibrillation (AF). Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Preoperative left ventricular ejection fraction and left atrium reverse remodeling after mitral regurgitation surgery.

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    Machado, Lucia R; Meneghelo, Zilda M; Le Bihan, David C S; Barretto, Rodrigo B M; Carvalho, Antonio C; Moises, Valdir A

    2014-11-06

    Left atrium enlargement has been associated with cardiac events in patients with mitral regurgitation (MR). Left atrium reverse remodeling (LARR) occur after surgical correction of MR, but the preoperative predictors of this phenomenon are not well known. It is therefore important to identify preoperative predictors for postoperative LARR. We enrolled 62 patients with chronic severe MR (prolapse or flail leaflet) who underwent successful mitral valve surgery (repair or replacement); all with pre- and postoperative echocardiography. LARR was defined as a reduction in left atrium volume index (LAVI) of ≥ 25%. Stepwise multiple regression analysis was used to identify independent predictors of LARR. LARR occurred in 46 patients (74.2%), with the mean LAVI decreasing from 85.5 mL/m2 to 49.7 mL/m2 (p <0.001). These patients had a smaller preoperative left ventricular systolic volume (p =0.022) and a higher left ventricular ejection fraction (LVEF) (p =0.034). LVEF was identified as the only preoperative variable significantly associated with LARR (odds ratio, 1.086; 95% confidence interval, 1.002-1.178). A LVEF cutoff value of 63.5% identified patients with LARR of ≥ 25% with a sensitivity of 71.7% and a specificity of 56.3%. LARR occurs frequently after mitral valve surgery and is associated with preoperative LVEF higher than 63.5%.

  13. Gadofosveset trisodium-enhanced magnetic resonance angiography of the left atrium-A feasibility study

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    Wagner, Moritz, E-mail: moritz.wagner@charite.d [Department of Radiology, Charite - University Hospital, Berlin (Germany); Rief, Matthias; Asbach, Patrick [Department of Radiology, Charite - University Hospital, Berlin (Germany); Vogtmann, Thomas [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Huppertz, Alexander [Imaging Science Institute Charite Berlin, Berlin (Germany); Beling, Mark [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Butler, Craig [Mazankowski Alberta Heart Institute, University of Alberta, Edmonton (Canada); Laule, Michael [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Warmuth, Carsten; Taupitz, Matthias; Hamm, Bernd; Lembcke, Alexander [Department of Radiology, Charite - University Hospital, Berlin (Germany)

    2010-08-15

    Aim: Imaging of the left atrium is regularly performed prior to pulmonary vein isolation. The aim of the study was to evaluate the feasibility of contrast-enhanced high-resolution magnetic resonance angiography (MRA) of the left atrium using the blood-pool contrast agent gadofosveset trisodium in comparison to noncontrast MRA. Materials and methods: Twenty consecutive patients were examined by free-breathing electrocardiogram-gated whole-heart MRA (reconstructed spatial resolution, 0.7 mm x 0.6 mm x 0.8 mm) with a noncontrast T2-prepared steady state free precession sequence (T2-prep SSFP) and a gadofosveset trisodium-enhanced inversion-recovery SSFP sequence (CE IR-SSFP). Contrast-to-noise ratio (CNR) of blood in the left atrium was determined. Depiction of the left atrium was rated by two radiologists in consensus. A cardiologist segmented the MR data sets and rated depiction of the left atrium. Results: Five of 20 patients had irregular breathing patterns with navigator efficiency less than 35% and were excluded from evaluation. CNR was significantly higher for CE IR-SSFP compared with T2-prep SSFP (18.4 {+-} 5.3 vs. 11.7 {+-} 3.5, p < 0.01). Depiction of the left atrium by T2-prep SSFP was rated as good in four patients, moderate in ten patients, and poor in one patient, whereas depiction of the left atrium by CE IR-SSFP was rated as excellent in nine patients, good in four patients, and moderate in two patients. CE IR-SSFP allowed for semiautomated segmentation of the left atrium in 15 patients, whereas T2-prep SSFP allowed for segmentation only in ten patients. Conclusion: Gadofosveset trisodium-enhanced MRA of the left atrium is feasible with significantly improved image quality compared to noncontrast MRA.

  14. The effect of percutaneous transcatheter occlusion of left atrial appendage on left atrium and adjacent anatomic structure in canine

    International Nuclear Information System (INIS)

    Yang Zhihong; Wu Hong; Qin Yongwen; Hu Jianqiang; Ding Zhongru; Liu Zongjun; Liu Biao; Zheng Xing

    2009-01-01

    Objective: To observe the effect of percutaneous transcatheter occlusion of left atrial appendage (LAA) with a new self-manufactured LAA occluder on left atrium and adjacent anatomic structure in canine. Methods: A new self-manufactured LAA occluder was implanted into the LAA through a transseptal catheter in 20 dogs. Before and after the procedure, the experimental dogs were anaesthetized and examined by transthoracic echocardiography (TTE) to measure the diameter and the volume of the left atrium, the left superior pulmonary vein flow velocity and the left atrioventricular valve flow velocity separately. The contrast radiography of the LAA and the left coronary arteriography were performed. Results: The new LAA occluder was implanted successfully in 14 dogs. No obvious changes in the diameter and the volume of the left atrium, in left superior pulmonary vein flow velocity and in left atrioventricular valve flow velocity were found. On arteriography, left circumflex artery was normally displayed after the procedure. No migration of the occluder was seen on TTE and angiography after procedure. Conclusion: Percutaneous transcatheter occlusion of left atrial appendage with a new self-manufactured LAA occluder has no obvious effect on left atrium and adjacent anatomic structure in experimental canine, which indicates that the new-type device is a safe and feasible occluder for LAA. (authors)

  15. Scimitar vein draining to the left atrium and a historical review of the scimitar syndrome

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    Holt, Peter D.; Berdon, Walter E.; Marans, Zvi; Griffiths, Sylvia; Hsu, Daphne

    2004-01-01

    Scimitar vein draining to the left atrium is the rarest of the pulmonary venolobar anomalies with less than a dozen reported cases. A case is reported of a patient whose plain film radiographic findings showed a typical scimitar vein but whose echocardiography showed normal pulmonary venous drainage. Cardiac catheterization confirmed drainage of the scimitar vein to the left atrium and systemic arterial supply which was embolized. The case described is used to review the history of ''scimitar syndrome'' with reflections on the significant contributions of Halasz and colleagues, who in 1956 helped define the anatomy, and Neill and colleagues, who in 1960 described the familial occurrence and clinical spectrum of the condition. (orig.)

  16. Transcatheter therapy in partially abnormal pulmonary venous return with additional drainage to the left atrium.

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    Luciano, Debora; Laux, Daniela; Boudjemline, Younes; Hascoët, Sébastien; Lusson, Jean-René; Sorensen, Clio; Ovaert, Caroline; Kreitmann, Bernard; Van Praagh, Richard; Fraisse, Alain

    2013-12-10

    A persistent anastomosis between the pulmonary veins that connect with the left atrium and the systemic vein that drains into the right atrium has occasionally been reported. We report characteristics and transcatheter therapy in partially abnormal pulmonary venous return with additional drainage to the left atrium. We retrospectively studied such patients in 5 institutions. Ten patients (6 girls) presented at a median age of 8 (0.1 to 54) years with 2 anatomic types: 8 vertical vein types with drainage of the left upper lobe to the innominate vein via a large vertical vein (left superior cardinal vein) and to the left atrium via the left upper pulmonary vein; and 2 scimitar vein (SV) types with drainage of the right middle and lower pulmonary veins into the inferior vena cava and to the left atrium via an anomalous connecting vein. Associated malformations were aortic coarctation (n=2) and secundum atrial septal defects (n=3). Two patients of the vertical vein type were operated. Transcatheter occlusion of the abnormal pulmonary venous return was performed in 7 cases, associated with occlusion of systemic arterial supply (n=2), secundum atrial septal closure (n=2), left upper pulmonary vein stenosis stenting (n=1), and coarctation stenting (n=1). Including previously published cases, 18 patients (13 vertical veins and 5 scimitar veins) underwent transcatheter repair. Patients over 40 years of age tend to be symptomatic at presentation (p=0.056). In partially abnormal pulmonary venous return with dual drainage, transcatheter therapy can be offered in the majority of patients. © 2013.

  17. Atlas-based mosaicing of 3D transesophageal echocardiography images of the left atrium

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    Mulder, H.W. (Harriët); Pluim, J.P.W.; Ren, B. (Ben); Haak, A. (Alexander); Viergever, M.A. (Max); Bosch, J.G. (Johan); Stralen, van M. (Marijn)

    2015-01-01

    3D transesophageal echocardiography (TEE) is routinely used for planning and guidance of cardiac interventions. However, the limited field-of-view dictates the compounding of multiple images for visualization of large structures, e.g. the left atrium (LA). Previously, we developed a TEE image

  18. A large tumour of the left atrium – A 10-year follow-up

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    Agnieszka M. Łebek-Szatańska

    2016-11-01

    Full Text Available Benign myxomas are the most common primary tumors in the left atrium of the heart, and they usually require urgent operative management. However, with the constant aging of the population and treatment of patients with severe concomitant diseases, an interesting question is the efficacy of the conservative approach. We present a case of a 75-year-old woman who was previously diagnosed with a left atrial myxoma, underwent an operation to resect it and then developed a recurrent tumor at the site of resection, which was found by control echocardiography 1.5 years later. She has been observed for over 10 years, as she repeatedly refused reoperation. In the setting of this example of a relatively favorable clinical course of left atrium myxoma, we discuss the current knowledge about the natural history of these tumors and the role of echocardiography in predicting their growth and complications.

  19. Bronchial compression by an enlarged left atrium in infants; a cause of hypovascularity of the left lung

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    Corr, L.; Hallidie-Smith, K.A.; McCarthy, P.A.; Lavender, J.P.

    1988-09-01

    In three infants seen recently at our institution we noted signs of compression of the left main bronchus associated with enlarged left atria. None of our cases demonstrated the more usual signs of hyperinflation which are a hyperlucent lung field, depressed hemidiaphragm and mediastinal shift away from the affected side. In addition, hypoperfusion of the left lung was noted in each case. We believe that bronchial compression due to an enlarged left atrium, with consequent hypoxic vasoconstriction is a clinically significant entity, which is not well described and may be unappreciated in infants in whom the typical signs of hyperinflation are absent.

  20. Ruptured Sinus of Valsalva Aneurysm into the Left Atrium with Multiple Fistulous Communications: A Rare Cause of Heart Failure

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    Yashwant Agrawal

    2015-01-01

    Full Text Available Ruptured noncoronary sinus of valsalva aneurysm with fistulous connections to multiple cardiac chambers has not been reported previously. We report a 66-year-old man who presented with worsening cough and exertional dyspnea. Transesophageal echocardiogram confirmed a large aneurysm involving the noncoronary cusp of the aortic sinus with aneurysmal extension to the left atrium. There were also two fistulous communications with the left atrium and one small fistulous connection with the right atrium. Open-heart surgery with aortic root replacement and reimplantation of coronary arteries along with primary closure and repair of aorta to the left atrial fistula was performed.

  1. Negative inotropism of terpenes on guinea pig left atrium: structure-activity relationships.

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    Vasconcelos, Carla M L; Oliveira, Ingrid S N; Santos, José N A; Souza, Américo A; Menezes-Filho, José E R; Silva Neto, Júlio A; Lima, Tamires C; de Sousa, Damião P

    2018-06-01

    The aim of this work was to evaluate the pharmacological effect of seven structurally related terpenes on the contractility of cardiac muscle. The effect of terpenes was studied on isolated electrically driven guinea pig left atrium. From concentration-response curves for inotropic effect were determined the EC 50 and relative potency of such terpenes. Our results revealed that all terpenes, except phytol, showed ability to reduce the contractile response of guinea pig left atrium. Further, relative potency was directly related to the number of isoprene units and to the lipophilicity of the compounds. For example, sesquiterpenes farnesol and nerolidol showed higher relative potency when compared with the monoterpenes citronellol, geraniol and nerol. We can conclude that most of the evaluated terpenes showed a promising negative inotropism on the atrial muscle. Future studies are necessary to investigate their action mechanism.

  2. Left atrium and pulmonary artery compression due to aortic aneurysm causing heart failure symptoms.

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    Jorge, Antonio José Lagoeiro; Martins, Wolney de Andrade; Moutinho, Victor M; Rezende, Juliano M; Alves, Patricia Y; Villacorta, Humberto; Silveira, Pedro F; Couto, Antonio A

    2018-05-09

    Patients with thoracic aortic aneurysm (TAA) are mostly asymptomatic and TAA is rarely related to heart failure (HF). We report the case of an 80-year-old female patient, with type A TAA without dissection, with right pulmonary artery and left atrium compression, who presented with HF, preserved ejection fraction and acute pulmonary edema. Copyright © 2018 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Rupture of the right upper pulmonary vein and left atrium caused by blunt chest trauma.

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    Osaka, Motoo; Nagai, Ryo; Koishizawa, Tadashi

    2017-11-01

    A 49-year-old man was transferred to our hospital by ambulance due to blunt chest trauma sustained in a car accident. Echocardiography and enhanced computed tomography showed hemopericardium without other vital organ damage. Emergent surgery was performed under strong suspicion of traumatic cardiac rupture. Careful inspection showed a rupture of the right upper pulmonary vein at the junction of the left atrium, a laceration of the inferior vena cava, and a left-side pericardium rupture, and they were repaired with running 4-0 polypropylene suture. Postoperative hemodynamics were stable. The patient was discharged ambulatory on postoperative day 15.

  4. Multislice CT imaging of ruptured left sinus of Valsalva aneurysm with fistulous track between left sinus and right atrium.

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    Pampapati, Praveenkumar; Rao, Hejmadi Tati Gururaj; Radhesh, Srinivasan; Anand, Hejjaji Krishnamurthy; Praveen, Lokkur Srinivasamurthy

    2011-01-01

    Sinus of valsalva aneurysm is a rare condition arising from any of the three aortic sinuses. Among them, an aneurysm arising from the left coronary sinus is the rarest. Most of these cases were earlier diagnosed using echocardiography and conventional angiography. But with the availability of advanced imaging modalities like 64 slice cardiac CT and MR modalities, this condition can be accurately assessed noninvasively. We report a case of ruptured aneurysm originating from the left coronary sinus with a long windsock type of fistulous track between the aneurysm and right atrium evaluated by 64 slice cardiac CT imaging. This was later confirmed perioperatively.

  5. The left atrium, atrial fibrillation, and the risk of stroke in hypertensive patients with left ventricular hypertrophy

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    Wachtell, K.; Devereux, R.B.; Lyle, P.A.

    2008-01-01

    was superior to atenolol-based treatment for reducing new-onset AF and complications, especially stroke, associated with new-onset or pre-existing AF. Potential mechanisms of AF prevention by angiotensin receptor blockade supported by LIFE results include greater reduction in left atrial size and LV......The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study provided extensive data on predisposing factors, consequences, and prevention of atrial fibrillation (AF) in patients with hypertension and left ventricular (LV) hypertrophy. Randomized losartan-based treatment...... hypertrophy. Differential effects of antihypertensive treatment on the left atrium and left ventricle may help prevent AF and reduce risk of stroke associated with hypertensive heart disease Udgivelsesdato: 2008/12...

  6. Validation of geometric measurements of the left atrium and pulmonary veins for analysis of reverse structural remodeling following ablation therapy

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    Rettmann, M. E.; Holmes, D. R., III; Gunawan, M. S.; Ge, X.; Karwoski, R. A.; Breen, J. F.; Packer, D. L.; Robb, R. A.

    2012-03-01

    Geometric analysis of the left atrium and pulmonary veins is important for studying reverse structural remodeling following cardiac ablation therapy. It has been shown that the left atrium decreases in volume and the pulmonary vein ostia decrease in diameter following ablation therapy. Most analysis techniques, however, require laborious manual tracing of image cross-sections. Pulmonary vein diameters are typically measured at the junction between the left atrium and pulmonary veins, called the pulmonary vein ostia, with manually drawn lines on volume renderings or on image cross-sections. In this work, we describe a technique for making semi-automatic measurements of the left atrium and pulmonary vein ostial diameters from high resolution CT scans and multi-phase datasets. The left atrium and pulmonary veins are segmented from a CT volume using a 3D volume approach and cut planes are interactively positioned to separate the pulmonary veins from the body of the left atrium. The cut plane is also used to compute the pulmonary vein ostial diameter. Validation experiments are presented which demonstrate the ability to repeatedly measure left atrial volume and pulmonary vein diameters from high resolution CT scans, as well as the feasibility of this approach for analyzing dynamic, multi-phase datasets. In the high resolution CT scans the left atrial volume measurements show high repeatability with approximately 4% intra-rater repeatability and 8% inter-rater repeatability. Intra- and inter-rater repeatability for pulmonary vein diameter measurements range from approximately 2 to 4 mm. For the multi-phase CT datasets, differences in left atrial volumes between a standard slice-by-slice approach and the proposed 3D volume approach are small, with percent differences on the order of 3% to 6%.

  7. Convolutional neural networks for the detection of diseased hearts using CT images and left atrium patches

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    Dormer, James D.; Halicek, Martin; Ma, Ling; Reilly, Carolyn M.; Schreibmann, Eduard; Fei, Baowei

    2018-02-01

    Cardiovascular disease is a leading cause of death in the United States. The identification of cardiac diseases on conventional three-dimensional (3D) CT can have many clinical applications. An automated method that can distinguish between healthy and diseased hearts could improve diagnostic speed and accuracy when the only modality available is conventional 3D CT. In this work, we proposed and implemented convolutional neural networks (CNNs) to identify diseased hears on CT images. Six patients with healthy hearts and six with previous cardiovascular disease events received chest CT. After the left atrium for each heart was segmented, 2D and 3D patches were created. A subset of the patches were then used to train separate convolutional neural networks using leave-one-out cross-validation of patient pairs. The results of the two neural networks were compared, with 3D patches producing the higher testing accuracy. The full list of 3D patches from the left atrium was then classified using the optimal 3D CNN model, and the receiver operating curves (ROCs) were produced. The final average area under the curve (AUC) from the ROC curves was 0.840 +/- 0.065 and the average accuracy was 78.9% +/- 5.9%. This demonstrates that the CNN-based method is capable of distinguishing healthy hearts from those with previous cardiovascular disease.

  8. Right-sided superior vena cava draining into the left atrium: a rare anomaly of systemic venous return

    International Nuclear Information System (INIS)

    Aminololama-Shakeri, Shadi; Wootton-Gorges, Sandra L.; Reyes, Melissa; Moore, Elizabeth H.; Pretzlaff, Robert K.

    2007-01-01

    The most commonly encountered systemic thoracic venous anomaly is a persistent left superior vena cava that drains into the right atrium via the coronary sinus. A much rarer systemic venous anomaly is that of isolated anomalous drainage of a normally positioned right superior vena cava (RSVC) into the left atrium (LA). This has been reported in approximately 20 patients with the diagnosis usually being made by cardiac catheterization. We report the case of a toddler with asymptomatic hypoxemia resulting from anomalous drainage of a normal RSVC into his LA. This was diagnosed non-invasively by contrast-enhanced chest CT. (orig.)

  9. Primary intimal sarcoma of the left atrium presenting with constitutional symptoms

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    Ferreira, António; Felgueiras, Paula; Silva, Augusta; Ribeiro, Carlos; Guerra, Diana; de Melo, Daniel Pereira; Manuel Lopes, José

    2017-01-01

    Abstract Intimal (spindle-cell) sarcomas are exceptionally rare and are highly aggressive cardiac tumors. The authors describe a case of a 43-year-old female, presenting with a 3-month history of constitutional symptoms with fever, night sweats, anorexia and weight loss, associated with productive cough and pleural effusion that was admitted with clinical suspicion of pulmonary tuberculosis. The patient developed sudden acute heart failure symptoms during hospitalization, leading to mechanical ventilation. Computed tomography scan with contrast showed a cardiac tumor filling the left atrium causing compression of pulmonary veins. Surgical resection was performed and histologic examination revealed an intimal sarcoma. Although commenced on adjuvant chemotherapy, local tumor recurrence occurred with pericardium invasion. The patient died within 4 months of initial diagnosis. This report aims to describe an unusual presentation of this rare disease entity, and to discuss its highly aggressive clinical course. PMID:28694971

  10. Cardiac dynamic magnetic resonance of a giant lung carcinoma invading the left atrium : do not let the imaging fool you

    NARCIS (Netherlands)

    Pozzoli, Alberto; Klinkenberg, Theo J.; De Maat, Gijs E.; Mariani, Massimo A.

    This study aimed to report on a non-small-cell lung cancer (NSCLC) originating from the right lung lower lobe and circulatory extension into the left atrium. Atrial involvement is an uncommon feature of advanced NSCLC, occurring in up to 10% of patients with bronchogenic carcinoma. In this case, the

  11. Determinants of Reverse Remodeling of the Left Atrium Following Transaortic Myectomy.

    Science.gov (United States)

    Nguyen, Anita; Schaff, Hartzell V; Nishimura, Rick A; Dearani, Joseph A; Geske, Jeffrey B; Lahr, Brian D; Ommen, Steve R

    2018-04-18

    In patients with hypertrophic cardiomyopathy (HCM), enlargement of the left atrium (LA) is associated with increased morbidity and mortality due to risk of atrial fibrillation (AF), stroke, and heart failure. In this study, we investigated whether LA reverse remodeling occurs following septal myectomy. Between March 2007 and July 2015, 656 patients underwent myectomy at our institution and had pre- and postoperative transthoracic echocardiographic (TTE) recording of LA volume index (LAVI). We reviewed clinical and echocardiographic data of these patients, and assessed for changes over time by comparing pre- and postoperative measurements. The median age was 56 (46, 65) years, and 370 (56%) were male. New York Heart Association Class III/IV dyspnea was present in 581 (89%). Preoperative TTE showed LAVI of 48 (38, 60) mL/m 2 . In patients with history of AF, preoperative LAVI was 57 (45, 68) mL/m 2 , and in those without AF, LAVI measured 45 (37, 57) mL/m 2 (p < 0.001). All patients underwent transaortic septal myectomy. Early postoperative TTE (4 [3, 5] days) demonstrated LAVI of 43 (36, 52) mL/m 2 (p < 0.001), and late postoperative TTE (2.0 [1.1, 4.1] years) showed LAVI of 38 (29, 47) mL/m 2 (p < 0.001). Preoperative LAVI was associated with late development of AF (p = 0.002). Left atrial volume decreases significantly following surgical relief of left ventricular outflow tract obstruction. Early changes likely reflect lower LA pressure due to gradient relief and abolishment of mitral regurgitation, and late reduction suggests continued reverse remodeling. Copyright © 2018. Published by Elsevier Inc.

  12. Brain Abscess Associated with Isolated Left Superior Vena Cava Draining into the Left Atrium in the Absence of Coronary Sinus and Atrial Septal Defect

    International Nuclear Information System (INIS)

    Erol, Ilknur; Cetin, I. Ilker; Alehan, Fuesun; Varan, Birguel; Ozkan, Sueleyman; Agildere, A. Muhtesem; Tokel, Kursad

    2006-01-01

    A previously healthy 12-year-old girl presented with severe headache for 2 weeks. On physical examination, there was finger clubbing without apparent cyanosis. Neurological examination revealed only papiledema without focal neurologic signs. Cerebral magnetic resonance imaging showed the characteristic features of brain abscess in the left frontal lobe. Cardiologic workup to exclude a right-to-left shunt showed an abnormality of the systemic venous drainage: presence of isolated left superior vena cava draining into the left atrium in the absence of coronary sinus and atrial septal defect. This anomaly is rare, because only a few other cases have been reported

  13. Prevalence and predictors of low voltage zones in the left atrium in patients with atrial fibrillation.

    Science.gov (United States)

    Huo, Yan; Gaspar, Thomas; Pohl, Matthias; Sitzy, Judith; Richter, Utz; Neudeck, Sebastian; Mayer, Julia; Kronborg, Mads Brix; Piorkowski, Christopher

    2017-06-10

    To describe the extent and distribution of low voltage zones (LVZ) in a large cohort of patients undergoing ablation for paroxysmal and persistent atrial fibrillation (AF), and to explore baseline predictors of LVZ in these patients. Consecutive patients who underwent a bipolar voltage map guided AF ablation, were enrolled. Voltage maps were conducted for each patient using 3-dimensional electroanatomical mapping system and LVZ were defined as areas of bipolar voltage voltage zones was present in 58 out of 292 patients with paroxysmal and 134 out of 247 persistent AF (P < 0.001). The area of LVZ was larger in patients with persistent as compare to paroxysmal AF, 5 cm2 (IQR 3-18.6) vs. 12.1 cm2 (IQR 3.6-28.5), P = 0.026, respectively. In the multivariate analysis age (OR 1.07, 95%CI 1.05-1.10, P < 0.001), female gender (OR 2.18, 95%CI 1.38-3.43, P = 0.001), sinoatrial node dysfunction (OR 3.90, 95%CI 1.24-12.21, P = 0.020), larger surface area of left atrium pr. cm2 (OR 1.01, 95%CI 1.00-1.02, P = 0.016), and persistent AF (OR 5.03, 95%CI 3.20-7.90, P<0.001) were associated with presence of LVZ. In a large cohort of patients undergoing ablation for AF, the prevalence of LVZ was higher and LVZ areas larger in patients with persistent as compared with paroxysmal AF. The most frequent localization of LVZ was anterior wall, septum and posterior wall. Presence of LVZ was associated with higher age, female gender, larger LA surface area, and sinoatrial node dysfunction. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  14. Effect of the Size of the Left Atrium on Sustained Sinus Rhythm in Patients Undergoing Mitral Valve Surgery and Concomitant Bipolar Radiofrequency Ablation for Atrial Fibrillation.

    Science.gov (United States)

    Avdagić, Harun; Sijerčić Avdagić, Selma; Pirić Avdagić, Melika; Antonič, Miha

    2017-12-01

    Atrial fibrillation is associated with systemic embolization and complications due to anticoagulant therapy. Radiofrequency ablation has been established as an effective and safe method for the treatment of atrial fibrillation. The aim of this study was to evaluate the effect of the size of the left atrium on the outcome of surgical radiofrequency ablation. Forty patients scheduled for elective mitral valve surgery and radiofrequency ablation were enrolled in the study. Group 1 consisted of patients with a left atrium diameter ≤5 cm and group 2 of patients with left atrium diameter >5 cm. The primary endpoint of the study was stable sinus rhythm 6 months postoperatively. At 6 months postoperatively, sinus rhythm was present in significantly more group 1 patients as compared with group 2 patients, i.e. 15 (75%) vs. 8 (40%), p=0.025. Multivariate analysis proved the size of the left atrium to be an independent predictor of the radiofrequency ablation outcome. Accordingly, the size of the left atrium was demonstrated to be an important predictor of the outcome of radiofrequency ablation for atrial fibrillation. A lower cut-off value of surgical reduction of the atria than previously reported should be considered in order to improve the radiofrequency ablation outcome.

  15. Crude extract and purified components isolated from the stems of Tinospora crispa exhibit positive inotropic effects on the isolated left atrium of rats

    DEFF Research Database (Denmark)

    Praman, Siwaporn; Mulvany, Michael J.; Williams, David E.

    2013-01-01

    of 5 bioactive compounds: higenamine, salsolinol, tyramine, adenosine and uridine. Higenamine, salsolinol (at low concentration) and tyramine acted via the adrenergic receptors to increase the force of the atrial contraction, whereas a high concentration of salsolinol acted indirectly by stimulating...... an increase in the force of contraction of the electrical field stimulated left atrium. This effect was inhibited by propranolol, atenolol, ICI-118,551, phentolamine and atropine. The positive inotropic effect on the reserpenized isolated left atrium of the Tinospora crispa extract was significantly inhibited...... by propranolol, atenolol and ICI-118,551. Phentolamine, on the other hand, caused potentiation and the effect was inhibited when propranolol was also added. Higenamine caused an increase in the force of contraction of the electrical field stimulated left atrium and this effect was significantly inhibited by ICI...

  16. Quantitative description of the 3D regional mechanics of the left atrium using cardiac magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kuklik, P; Molaee, P; Ganesan, A N; Brooks, A G; Worthley, S G; Sanders, P; Podziemski, P

    2014-01-01

    The left atrium (LA) plays an important role in the maintenance of hemodynamic and electrical stability of the heart. One of the conditions altering the atrial mechanical function is atrial fibrillation (AF), leading to an increased thromboembolic risk due to impaired mechanical function. Preserving the regions of the LA that contribute the greatest to atrial mechanical function during curative strategies for AF is important. The purpose of this study is to introduce a novel method of regional assessment of mechanical function of the LA. We used cardiac MRI to reconstruct the 3D geometry of the LA in nine control and nine patients with paroxysmal atrial fibrillation (PAF). Regional mechanical function of the LA in pre-defined segments of the atrium was calculated using regional ejection fraction and wall velocity. We found significantly greater mechanical function in anterior, septal and lateral segments as opposed to roof and posterior segments, as well as a significant decrease of mechanical function in the PAF group. We suggest that in order to minimize the impact of the AF treatment on global atrial mechanical function, damage related to therapeutic intervention, such as catheter ablation, in those areas should be minimized. (paper)

  17. Esophageal achalasia compressing left atrium diagnosed by echocardiography using a liquid containing carbon dioxide in a 21-year-old woman with Turner syndrome.

    Science.gov (United States)

    Park, Man Je; Song, Bong Gun; Lee, Hyoun Soo; Kim, Ki Hoon; Ok, Hea Sung; Kim, Byeong Ki; Park, Yong Hwan; Kang, Gu Hyun; Chun, Woo Jung; Oh, Ju Hyeon

    2012-01-01

    Extrinsic compression of the left atrium by the esophagus, the stomach, or both is an uncommon but important cause of hemodynamic compromise. Achalasia is a motility disorder characterized by impaired relaxation of the lower esophageal sphincter and dilatation of the distal two thirds of the esophagus. Echocardiographic imaging after oral ingestion of liquid containing carbon dioxide allowed for differentiation between a compressive vascular structure and the esophagus. We report a rare case of esophageal achalasia compressing the left atrium diagnosed by echocardiography using a liquid containing carbon dioxide in a 21-year-old woman with Turner syndrome. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. The application and value of 64 multislice spiral CT of left atrium and pulmonary vein in radio-frequency ablation of atrial fibrillation

    International Nuclear Information System (INIS)

    Guo Xi; Lv Biao; Zhang Zhaoqi; Zhao Yike; Jiang Hong; Ma Changsheng; Yu Ronghui; Wang Xue; Cao Hainian

    2008-01-01

    Objective: Analyzing the left atrium and pulmonary vein morphologically by 64 multislice spiral CT (MSCT) scan to guide the catheter ablation of Atrial fibrillation. Methods: Two hundred and thirty-two patients (146 cases in atrial fibrillation group and 86 cases in control group) received 64 MSCT examination of the left atrium and pulmonary vein. The incidence of anatomical variation of pulmonary vein was compared between atrial fibrillation group and control group. For each group, the anatomical morphology of every pulmonary vein and the auricle of left atrium was analyzed, the diameter of the orifice of each pulmonary vein and the size of left atrium were measured. Results: Sixty-four MSCT of left atrium and pulmonary vein could demonstrate detailed connecting type between left atrium and pulmonary veins and the possible anatomical variation. Anatomical variation of pulmonary vein in this study accounted for 16.8% (39/232) of total sample. For both groups, orifices of pulmonary veins appeared oval and their superoinferior diameters were larger than their anteroposterior diameters. There was significant difference in the inner diameter of left atrium between atrial fibrillation group and control group [atrial fibrillation group: (39.47 ± 8.98) mm, control group: (36.94±5.49) mm, P=0.02], while there was no difference in the diameters of orifices of pulmonary veins between two groups [superoinferior diameters of pulmonary veins in atrial fibrillation group: left-up (18.15±1.35) mm, left-down (16.96±1.18) mm, right-up (17.50±1.12) mm, fight-down (17.65±0.94) mm, superoinferior diameters of pulmonary veins in control group: left-up (18.07±0.94) mm, left-down (17.50±0.57) mm, right-up (18.03±1.02) mm, fight-down (17.94±0.76) mm, the corresponding P>0.05, respectively, anteroposterior diameters of pulmonary veins in atrial fibrillation group: left-up (12.26±1.89) mm, left-down (11.96±0.61) mm, right-up (12.32± 1.08) mm, fight-down (12.39±0.95) mm

  19. A comparison of the histopathologic pattern of the left atrium in canine dilated cardiomyopathy and chronic mitral valve disease.

    Science.gov (United States)

    Janus, Izabela; Noszczyk-Nowak, Agnieszka; Nowak, Marcin; Ciaputa, Rafał; Kandefer-Gola, Małgorzata; Pasławska, Urszula

    2016-01-05

    Dilated cardiomyopathy (DCM) and chronic mitral valve disease (CMVD) in dogs are associated with heart chamber enlargement, also of the left atrium. DCM is often accompanied by rhythm disturbances (mainly atrial fibrillation or ventricular arrhythmias). In CMVD, arrhythmias are observed less frequently. It is still unclear whether left atrial enlargement in these diseases results from volume overload or if it is also connected with other factors (e.g. rhythm disturbances). This study was conducted on the left atrial myocardial specimens from 31 dogs, including those from 16 dogs with clinically diagnosed DCM and 15 dogs with CMVD. After fixation and staining (using haematoxylin-eosin and Masson-Goldner trichrome stain), the specimens underwent evaluation. Parenchymal changes (fibrosis, fatty infiltration, and vessel narrowing), degenerative changes (loss of striation, changes in cardiomyocyte structure, and abnormal cell nuclei) and the presence of inflammatory infiltrates were assessed. More interstitial fibrosis (median 4 vs. 2.5 grid fields; p < 0.05) and less perivascular fibrosis (median score 1 vs. 2; p < 0.05) was observed in the DCM group compared to the CMVD group. Moreover, less distinct vessel narrowing was observed in the DCM group than in the CMVD group (median lumen area ratio 0.3 vs. 0.26 respectively; p < 0.05). Dogs with DCM showed more strongly defined degenerative changes than the CMVD dogs (median nuclei enlargement score 3 vs. 1, median loss of striation score 3 vs. 2 and median structural alterations score 3 vs. 2, respectively; p < 0.05). The obtained results indicate a different nature of changes occurring in the left atrial myocardium of dogs with DCM compared to dogs with mitral valve disease, including differences in vessel narrowing, cardiomyocyte degeneration and in the distribution of connective tissue.

  20. Automatic intra-operative generation of geometric left atrium/pulmonary vein models from rotational X-ray angiography.

    Science.gov (United States)

    Meyer, Carsten; Manzke, Robert; Peters, Jochen; Ecabert, Olivier; Kneser, Reinhard; Reddy, Vivek Y; Chan, Raymond C; Weese, Jürgen

    2008-01-01

    Pre-procedural imaging with cardiac CT or MR has become popular for guiding complex electrophysiology procedures such as those used for atrial fibrillation ablation therapy. Electroanatomical mapping and ablation within the left atrium and pulmonary veins (LAPV) is facilitated using such data, however the pre-procedural anatomy can be quite different from that at the time of intervention. Recently, a method for intra-procedural LAPV imaging has been developed based on contrast-enhanced 3-D rotational X-ray angiography (3-D RA). These intraprocedural data now create a compelling need for rapid and automated extraction of the LAPV geometry for catheter guidance. We present a new approach to automatic intra-procedural generation of LAPV surfaces from 3-D RA volumes. Using model-based segmentation, our technique is robust to imaging noise and artifacts typical of 3-D RA imaging, strongly minimizes the user interaction time required for segmentation, and eliminates inter-subject variability. Our findings in 33 patients indicate that intra-procedural LAPV surface models accurately represent the anatomy at the time of intervention and are comparable to pre-procedural models derived from CTA or MRA.

  1. Characteristics of complex fractionated atrial electrogram in the electroanatomically remodeled left atrium of patients with atrial fibrillation

    International Nuclear Information System (INIS)

    Park, Jae-Hyung; Kim, Jong-Youn; Park, Sang-Weon

    2010-01-01

    Complex fractionated atrial electrogram (CFAE) guided ablation is effective in some patients with persistent atrial fibrillation (PeAF), but the pattern of CFAE may be different in the remodeled left atrium (LA). In 100 AF patients (83 males, 55.0±10.6 years old) with AF (51 paroxysmal AF (PAF), 49 PeAF) who underwent catheter ablation, CFAE cycle length (CL) and distribution (NavX 3D map) were compared according to the LA volume (3D-CT) and endocardial voltage (during high right atrial pacing 500-ms (Vol PACE ) and AF (Vol AF ; NavX). The mean CFAE-CL was longer (P=0.003) and the % area CFAE was smaller (P=0.006) in patients with LA ≥125 ml than those with PACE AF PACE <1.7 mV than those with ≥1.7 mV (P=0.006). The incidence of septal CFAE was consistently high, regardless of the degree of LA remodeling. In the AF patients with an electroanatomically remodeled LA, the % area of CFAE was smaller and mean CFAE-CL was longer than in those with a less remodeled LA. However, the majority of CFAE are consistently positioned on the septum in the remodeled LA. (author)

  2. A Combined Random Forests and Active Contour Model Approach for Fully Automatic Segmentation of the Left Atrium in Volumetric MRI

    Directory of Open Access Journals (Sweden)

    Chao Ma

    2017-01-01

    Full Text Available Segmentation of the left atrium (LA from cardiac magnetic resonance imaging (MRI datasets is of great importance for image guided atrial fibrillation ablation, LA fibrosis quantification, and cardiac biophysical modelling. However, automated LA segmentation from cardiac MRI is challenging due to limited image resolution, considerable variability in anatomical structures across subjects, and dynamic motion of the heart. In this work, we propose a combined random forests (RFs and active contour model (ACM approach for fully automatic segmentation of the LA from cardiac volumetric MRI. Specifically, we employ the RFs within an autocontext scheme to effectively integrate contextual and appearance information from multisource images together for LA shape inferring. The inferred shape is then incorporated into a volume-scalable ACM for further improving the segmentation accuracy. We validated the proposed method on the cardiac volumetric MRI datasets from the STACOM 2013 and HVSMR 2016 databases and showed that it outperforms other latest automated LA segmentation methods. Validation metrics, average Dice coefficient (DC and average surface-to-surface distance (S2S, were computed as 0.9227±0.0598 and 1.14±1.205 mm, versus those of 0.6222–0.878 and 1.34–8.72 mm, obtained by other methods, respectively.

  3. The effects of microsphere injections into the left atrium on the myocardial blood supply measured by thermal conductance probes

    International Nuclear Information System (INIS)

    Hahn, N.; Eichelkraut, W.; Kropp, J.; Bonn Univ.

    1990-01-01

    210 measurements made during experiments on 66 dogs under propionyl-promazine/pentobarbital narcosis were newly analysed to verify a possible influence of microspheres (9 μm diameter) injected into the left atrium on microcirculation. Using 20 additional dogs in identically performed experiments, the myocardial perfusion was measured using thermal conductance probes, following injections of isotonic NaCl solution, Ringer's solution, 5% glucose, the subject's blood, and isotonic NaCl solution mixed with the surface-active substance Tween 80 R . These supension media were injected both with and without unlabelled microspheres (8.6 μm diameter). The results led to the following conclusions. An obligatory decrease in the blood supply as the result of a mechanical blocking of capillaries by microspheres can be ruled out. The particles, the suspension media, and a suspension temperature not sufficiently adjusted to the body temperature induce reactive negative or positive changes in the microcirculation of the myocardium. Solutions containing particles cause, in the majority of cases, a decrease. The suspension medium with the smallest effect proved to be isotonic NaCl solution. From the results one can conclude that artefacts may arise from the application of the heat conductance probe method when the temperatures are not perfectly matched. However, the injected solution itself can often lead to various reactions in microcirculation which may last up to 5 min. It is advisable to allow at least 6 min to elapse after reactive changes have faded before administering the next injection. (orig./MG)

  4. Computer-based automated left atrium segmentation and volumetry from ECG-gated coronary CT angiography data. Comparison with manual slice segmentation and ultrasound planimetric methods

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, R.W.; Kraus, B.; Kerl, J.M.; Lehnert, T.; Vogl, T.J. [Universitaetsklinikum Frankfurt (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Bernhardt, D.; Vega-Higuera, F. [Siemens AG, Healthcare Sector, Forchheim (Germany). Computed Tomography; Ackermann, H. [Universitaetsklinikum Frankfurt (Germany). Inst. fuer Biostatistik und Mathematische Modellierung

    2010-12-15

    Purpose: Enlargement of the left atrium is a risk factor for cardiovascular or cerebrovascular events. We evaluated the performance of prototype software for fully automated segmentation and volumetry of the left atrium. Materials and Methods: In 34 retrospectively ECG-gated coronary CT angiography scans, the end-systolic (LAVsys) and end-diastolic (LAVdia) volume of the left atrium was calculated fully automatically by prototype software. Manual slice segmentation by two independent experienced radiologists served as the reference standard. Furthermore, two independent observers calculated the LAV utilizing two ultrasound planimetric methods ('area length' and 'prolate ellipse') on CTA images. Measurement periods were compared for all methods. Results: The left atrial volumes calculated with the prototype software were in excellent agreement with the results from manual slice segmentation (r = 0.97 - 0.99; p < 0.001; Bland-Altman) with excellent interobserver agreement between both radiologists (r = 0.99; p < 0.001). Ultrasound planimetric methods clearly showed a higher variation (r = 0.72 - 0.86) with moderate interobserver agreement (r = 0.51 - 0.79). The measurement period was significantly lower with the software (267 {+-} 28 sec; p < 0.001) than with ultrasound methods (431 {+-} 68 sec) or manual slice segmentation (567 {+-} 91 sec). Conclusion: The prototype software showed excellent agreement with manual slice segmentation with the least time consumption. This will facilitate the routine assessment of the LA volume from coronary CTA data and therefore risk stratification. (orig.)

  5. Left ventricular ejection fraction and left atrium diameter related to new-onset atrial fibrillation following acute myocardial infarction: a systematic review and meta-analysis.

    Science.gov (United States)

    Zeng, Rui-Xiang; Chen, Mao-Sheng; Lian, Bao-Tao; Liao, Peng-Da; Zhang, Min-Zhou

    2017-10-06

    New-onset atrial fibrillation (NOAF) occurs frequently in patients with acute myocardial infarction (AMI), and is associated with increased subsequent cardiovascular mortality. However, only a few studies directly evaluated the relationship of left ventricular ejection fraction (LVEF) or left atrium diameter (LAD) and NOAF following AMI. MEDLINE ® , EMBASE ® and the Cochrane Library were carried out to find studies until January 2017. Pooled mean difference (MD) and 95% confidence interval (CI) were calculated to evaluate the value of LVEF and LAD in the prediction of NOAF after AMI. We performed sensitivity analyses to explore the potential sources of heterogeneity. Statistical analyses were carried out using the Revman 5.3. We included 10 qualifying studies comprising a total of 708 patients with NOAF and 6785 controls. Overall, decreased LVEF and increased LAD levels had a significant positive association with NOAF in patients with AMI. The MD in the LVEF levels between the patients with and those without NOAF was -4.91 units (95% Cl: -5.70 to -4.12), test for overall effect z-score = 12.18 ( p < 0.00001, I 2 = 35%). Moreover, in a subgroup analysis, the MD for LAD and NOAF was 2.55 units (95% Cl: 1.91 to 3.19), test for overall effect z-score = 7.80 ( p < 0.00001, I 2 = 57%). Our meta-analysis demonstrated that both decreased LVEF and increased LAD levels were associated with greater risk of NOAF following AMI.

  6. Impact of ECG gating in contrast-enhanced MR angiography for the assessment of the pulmonary veins and the left atrium anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, M.; Buecker, A.; Muehlenbruch, G.; Guenther, R.W.; Spuentrup, E. [Klinik fuer Radiologische Diagnostik, Universitaetsklinikum RWTH Aachen (Germany); Schauerte, P. [Medizinische Klinik 1, Universitaetsklinikum RWTH Aachen (Germany)

    2006-02-15

    Purpose: Implementation of ECG gating in contrast-enhanced MR angiography (ceMRA) for improved visualization of the pulmonary veins, the left atrium, and the thoracic vessels. Materials and Methods: CeMRA was performed on twelve patients with a history of recurrent atrial fibrillation for the purpose of an intra-individual comparison with and without ECG gating on a 1.5 Tesla MR system (Gyroscan Intera, Philips Medical Systems, Best, NL). Objective image quality parameters such as the signal-to-noise ratio (SNR) of the blood and the contrast-to-noise ratio (CNR) between the blood and myocardium or lung parenchyma were analyzed. The contour sharpness of the pulmonary veins, left atrium, ascending aorta, and pulmonary trunk was also measured. In addition, the artifact level was subjectively assessed by two observers blinded with respect to the sequence parameters. Statistically significant differences (p<0.05) between the procedures were analyzed using the Wilcoxon test and Pearson Chi-square test. Results: The use of ECG gating in ceMRA significantly reduced artifacts caused by cardiac motion and vessel pulsation. This in turn lead to a significant increase in the contour sharpness of the left atrium and the thoracic vessels. In addition, higher SNR and CNR were found using ECG-gated ceMRA compared to standard ceMRA. Conclusion: The use of ECG gating in ceMRA results in artifact-free and sharper delineation of the structures of the heart and thoracic vessels. (orig.)

  7. Impact of ECG gating in contrast-enhanced MR angiography for the assessment of the pulmonary veins and the left atrium anatomy

    International Nuclear Information System (INIS)

    Katoh, M.; Buecker, A.; Muehlenbruch, G.; Guenther, R.W.; Spuentrup, E.; Schauerte, P.

    2006-01-01

    Purpose: Implementation of ECG gating in contrast-enhanced MR angiography (ceMRA) for improved visualization of the pulmonary veins, the left atrium, and the thoracic vessels. Materials and Methods: CeMRA was performed on twelve patients with a history of recurrent atrial fibrillation for the purpose of an intra-individual comparison with and without ECG gating on a 1.5 Tesla MR system (Gyroscan Intera, Philips Medical Systems, Best, NL). Objective image quality parameters such as the signal-to-noise ratio (SNR) of the blood and the contrast-to-noise ratio (CNR) between the blood and myocardium or lung parenchyma were analyzed. The contour sharpness of the pulmonary veins, left atrium, ascending aorta, and pulmonary trunk was also measured. In addition, the artifact level was subjectively assessed by two observers blinded with respect to the sequence parameters. Statistically significant differences (p<0.05) between the procedures were analyzed using the Wilcoxon test and Pearson Chi-square test. Results: The use of ECG gating in ceMRA significantly reduced artifacts caused by cardiac motion and vessel pulsation. This in turn lead to a significant increase in the contour sharpness of the left atrium and the thoracic vessels. In addition, higher SNR and CNR were found using ECG-gated ceMRA compared to standard ceMRA. Conclusion: The use of ECG gating in ceMRA results in artifact-free and sharper delineation of the structures of the heart and thoracic vessels. (orig.)

  8. Fully automatic segmentation of left atrium and pulmonary veins in late gadolinium-enhanced MRI: Towards objective atrial scar assessment.

    Science.gov (United States)

    Tao, Qian; Ipek, Esra Gucuk; Shahzad, Rahil; Berendsen, Floris F; Nazarian, Saman; van der Geest, Rob J

    2016-08-01

    To realize objective atrial scar assessment, this study aimed to develop a fully automatic method to segment the left atrium (LA) and pulmonary veins (PV) from late gadolinium-enhanced (LGE) magnetic resonance imaging (MRI). The extent and distribution of atrial scar, visualized by LGE-MRI, provides important information for clinical treatment of atrial fibrillation (AF) patients. Forty-six AF patients (age 62 ± 8, 14 female) who underwent cardiac MRI prior to RF ablation were included. A contrast-enhanced MR angiography (MRA) sequence was acquired for anatomy assessment followed by an LGE sequence for LA scar assessment. A fully automatic segmentation method was proposed consisting of two stages: 1) global segmentation by multiatlas registration; and 2) local refinement by 3D level-set. These automatic segmentation results were compared with manual segmentation. The LA and PVs were automatically segmented in all subjects. Compared with manual segmentation, the method yielded a surface-to-surface distance of 1.49 ± 0.65 mm in the LA region when using both MRA and LGE, and 1.80 ± 0.93 mm when using LGE alone (P automatic and manual segmentation was comparable to the interobserver difference (P = 0.8 in LA region and P = 0.7 in PV region). We developed a fully automatic method for LA and PV segmentation from LGE-MRI, with comparable performance to a human observer. Inclusion of an MRA sequence further improves the segmentation accuracy. The method leads to automatic generation of a patient-specific model, and potentially enables objective atrial scar assessment for AF patients. J. Magn. Reson. Imaging 2016;44:346-354. © 2016 Wiley Periodicals, Inc.

  9. 3D patient-specific models for left atrium characterization to support ablation in atrial fibrillation patients.

    Science.gov (United States)

    Valinoti, Maddalena; Fabbri, Claudio; Turco, Dario; Mantovan, Roberto; Pasini, Antonio; Corsi, Cristiana

    2018-01-01

    Radiofrequency ablation (RFA) is an important and promising therapy for atrial fibrillation (AF) patients. Optimization of patient selection and the availability of an accurate anatomical guide could improve RFA success rate. In this study we propose a unified, fully automated approach to build a 3D patient-specific left atrium (LA) model including pulmonary veins (PVs) in order to provide an accurate anatomical guide during RFA and without PVs in order to characterize LA volumetry and support patient selection for AF ablation. Magnetic resonance data from twenty-six patients referred for AF RFA were processed applying an edge-based level set approach guided by a phase-based edge detector to obtain the 3D LA model with PVs. An automated technique based on the shape diameter function was designed and applied to remove PVs and compute LA volume. 3D LA models were qualitatively compared with 3D LA surfaces acquired during the ablation procedure. An expert radiologist manually traced the LA on MR images twice. LA surfaces from the automatic approach and manual tracing were compared by mean surface-to-surface distance. In addition, LA volumes were compared with volumes from manual segmentation by linear and Bland-Altman analyses. Qualitative comparison of 3D LA models showed several inaccuracies, in particular PVs reconstruction was not accurate and left atrial appendage was missing in the model obtained during RFA procedure. LA surfaces were very similar (mean surface-to-surface distance: 2.3±0.7mm). LA volumes were in excellent agreement (y=1.03x-1.4, r=0.99, bias=-1.37ml (-1.43%) SD=2.16ml (2.3%), mean percentage difference=1.3%±2.1%). Results showed the proposed 3D patient-specific LA model with PVs is able to better describe LA anatomy compared to models derived from the navigation system, thus potentially improving electrograms and voltage information location and reducing fluoroscopic time during RFA. Quantitative assessment of LA volume derived from our 3D LA

  10. Successful treatment of an acute infective endocarditis secondary to fish bone penetrating into left atrium caused by Granulicatella adiacens and Candida albicans: A case report.

    Science.gov (United States)

    Tong, Ya Ling; Qu, Ting Ting; Xu, Jia; Chen, Nai Yun; Yang, Mei Fang

    2017-12-01

    Infective endocarditis caused by a foreign body of the upper digestive tract is rare. We report a rare case of Granulicatella adiacens and Candida albicans coinfection acute endocarditis combined with systematic embolization caused by a fish bone from the esophagus penetrating into the left atrium. A 42-year-old woman was admitted to our hospital because of fever, abdominal pain, headache, and right limb weakness. Clinical examination indicated endocarditis and systemic embolisms secondary to a fish bone from the esophagus penetrating into the left atrium. The emergency surgery confirmed the diagnosis. Cultures of blood and vegetation show G adiacens and C albicans. Antimicrobial therapy lasted 6 weeks after surgery. The patient was discharged with excellent condition7 weeks after hospitalization and was well when followed 6 months later. The successful treatment of this patient combines quick diagnosis, timely surgery, and effective antimicrobial regimen. This rare possibility should be kept up in mind in acute infective endocarditis cases. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  11. Extended resections of non-small cell lung cancers invading the aorta, pulmonary artery, left atrium, or esophagus: can they be justified?

    Science.gov (United States)

    Reardon, Emily S; Schrump, David S

    2014-11-01

    T4 tumors that invade the heart, great vessels, or esophagus comprise a heterogenous group of locally invasive lung cancers. Prognosis depends on nodal status; this relationship has been consistently demonstrated in many of the small series of extended resection. Current National Comprehensive Cancer Network guidelines do not recommend surgery for T4 extension with N2-3 disease (stage IIIB). However, biopsy-proven T4 N0-1 (stage IIIA) may be operable. Localized tumors with invasion of the aorta, pulmonary artery, left atrium, or esophagus represent a small subset of T4 disease. Acquiring sufficient randomized data to provide statistical proof of a survival advantage for patients undergoing extended resections for these neoplasms will likely never be possible.Therefore, we are left to critically analyze current documented experience to make clinical decisions on a case-by-case basis.It is clear that the operative morbidity and mortality of extended resections for locally advanced T4 tumors have significantly improved over time,yet the risks are still high. The indications for such procedures and the anticipated outcomes should be clearly weighed in terms of potential perioperative complications and expertise of the surgical team. Patients with T4 N0-1 have the best prognosis and with complete resection may have the potential for cure. The use of induction therapy and surgery for advanced T4 tumors may improve survival. Current data suggest that for tumors that invade the aorta, pulmonary artery,left atrium, or esophagus, resection should be considered in relation to multidisciplinary care.For properly selected patients receiving treatment at high volume, experienced centers, extended resections may be warranted. Published by Elsevier Inc.

  12. Left atrium volume index is influenced by aortic stiffness and central pulse pressure in type 2 diabetes mellitus patients: a hemodynamic and echocardiographic study.

    Science.gov (United States)

    Zapolski, Tomasz; Wysokiński, Andrzej

    2013-03-04

    Left atrial volume index (LAVI) has recently emerged as a useful biomarker for risk stratification and risk monitoring in many clinical settings. Many hemodynamic factors such as preload and afterload have an effect on evaluating left atrium function. This study was performed to investigate the relationship between LAVI and aortic stiffness index (ASI) and selected markers characterizing hemodynamic state in patients with type 2 diabetes mellitus (DM2). The study population consisted of 100 patients (56 men, 44 women), 67.2 (±10.9) years old DM2, scheduled for routine coronary angiography. Standard transthoracic echocardiography was used to measure parameters needed for calculation of LAVI and ASI. During invasive procedures, central pulse pressure (CPP) in the ascendens aorta and left ventricle end-diastolic pressure (LVEDP) were recorded. Selected laboratory parameters were obtained, including lipidogram, serum uric acid, hs-CRP, fibrinogen, cTnT, myoglobin, BNP, HbA1C, creatinine, and GFR. Both LAVI and ASI were greater and CPP and LVEDP were markedly elevated in DM2 patients compared to controls. The independent predictors of LAVI were ASI (ß=0.331; p=0.011), CPP (ß=0.312; p=0.020), LVEDP (ß=0.381; p=0.006), HbA1C (ß=0.379; p=0.008), and BNP (ß=0,423; pDM2 patients.

  13. Paroxysmal postprandial atrial fibrilation suppressed by laparoscopic repair of a giant paraesophageal hernia compressing the left atrium.

    Science.gov (United States)

    Cristian, Daniel A; Constantin, Alin S; Barbu, Mariana; Spătaru, Dan; Burcoș, Traean; Grama, Florin A

    2015-03-01

    We present the case of a patient with a giant paraesophageal hernia associated with paroxysmal postprandial atrial fibrillation that was suppressed after surgery. The imaging investigations showed the intrathoracic displacement of a large part of the stomach, which pushed the left atrial wall causing atrial fibrillation. The laparoscopic surgical repair acted as sole treatment for this condition.

  14. Diagnosing Paroxysmal Atrial Fibrillation in Patients With Ischemic Strokes and Transient Ischemic Attacks Using Echocardiographic Measurements of Left Atrium Function

    DEFF Research Database (Denmark)

    Skaarup, Kristoffer Grundtvig; Christensen, Hanne Krarup; Høst, Nis

    2016-01-01

    Twenty-five to 35 percentage of stroke cases are cryptogenic, and it has been demonstrated that paroxysmal atrial fibrillation (AF) is the causal agent in up to 25% of these incidents. The purpose of this study was to investigate if left atrial (LA) parameters have value for diagnosing paroxysmal...... with paroxysmal AF. However, the atrial measurements evaluating LA function (min LA volume and LA emptying fraction) were significantly different (LA emptying fraction: 45% ± 10% vs 50% ± 10%, p = 0.004; minimal LA volume: 30.2 ml ± 17.3 ml vs 24 ml ± 10 ml, p = 0.035 in patients with paroxysmal AF, even after...

  15. Mechanical dyssynchrony of the left atrium during sinus rhythm is associated with history of stroke in patients with atrial fibrillation.

    Science.gov (United States)

    Ciuffo, Luisa; Inoue, Yuko Y; Tao, Susumu; Gucuk Ipek, Esra; Balouch, Muhammad; Lima, Joao A C; Nazarian, Saman; Spragg, David D; Marine, Joseph E; Berger, Ronald D; Calkins, Hugh; Ashikaga, Hiroshi

    2018-04-01

    We sought to evaluate the relationship between left atrial (LA) mechanical dyssynchrony and history of stroke or transient ischaemic attack (TIA) in patients with atrial fibrillation (AF). We hypothesized that mechanical dyssynchrony of the LA is associated with history of stroke/TIA independent of LA function and Cardiac failure, Hypertension, Age, Diabetes, Stroke/transient ischaemic attack (TIA), VAscular disease, and Sex category (CHA2DS2-VASc) score in patients with AF. We conducted a cross-sectional study of 246 patients with a history of AF (59 ± 10 years, 29% female, 26% non-paroxysmal AF) referred for catheter ablation to treat drug-refractory AF who underwent preablation cardiac magnetic resonance (CMR) in sinus rhythm. Using tissue-tracking CMR, we measured the LA longitudinal strain and strain rate in each of 12 equal-length segments in two- and four-chamber views. We defined indices of LA mechanical dyssynchrony, including the standard deviation of the time to the peak longitudinal strain (SD-TPS). Patients with a prior history of stroke or TIA (n = 23) had significantly higher SD-TPS than those without (n = 223) (39.9 vs. 23.4 ms, P stroke/TIA after adjusting for the CHA2DS2-VASc score, LA minimum index volume, and the peak LA longitudinal strain (P stroke/TIA more accurately than CHA2DS2-VASc score alone (c-statistics: 0.82 vs. 0.75, P stroke/TIA in patients with AF.

  16. Influence of heart rhythm, breathing and arm position during computed tomography scanning on the registration accuracy of electro anatomical map (EAM) images, left atrium three-dimensional computed tomography angiography images, and fluoroscopy time during ablation to treat atrial fibrillation

    International Nuclear Information System (INIS)

    Chono, Taiki; Shimoshige, Shinya; Yoshikawa, Kenta; Mizonobe, Kazuhusa; Ogura, Keishi

    2013-01-01

    In CARTOMERGE for treatment of atrial fibrillation (AF) by ablation, by integrating electro anatomical map (EAM) and left atrium three-dimensional computed tomography angiography (3D-CTA) images, identification of the ablation points is simplified and the procedure can be made carried out more rapidly. However, the influence that heart rhythm, breathing and arm position during CT scanning have on registration accuracy and fluoroscopy time is not clear. To clarify the influence on registration accuracy and fluoroscopy time of heart rhythm, breathing and arm position during CT scanning. The patients were CT-scanned during both sinus rhythm (SR) and AF in each study subject. We evaluated the registration accuracy of images reconstructed between the cardiac cycle and assessed the registration accuracy and fluoroscopy time of images obtained during inspiratory breath-hold, expiratory breath-hold and up and down position of the arm. Although the registration accuracy of the EAM image and left atrium 3D-CTA image showed a significant difference during SR, no significant difference was seen during AF. Expiratory breath-hold and down position of the arm resulted in the highest registration accuracy and the shortest fluoroscopy time. However, arm position had no significant effect on registration accuracy. Heart rhythm and breathing during CT scanning have a significant effect on the registration accuracy of EAM images, left atrium 3D-CTA images, and fluoroscopy time. (author)

  17. MDCT Evaluation of Left Atrium and Pulmonary Vein in the Patients with Atrial Fibrillation: Comparison with the Non-Atrial Fibrillation Group

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Jung; Choi, Eun Jeong; Ham, Soo Yeon; Oh, Yu Whan; Kim, Young Hoon [Anam Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Yong, Hwan Seok [Korea University Guro Hospital, Seoul (Korea, Republic of); Yang, Kyung Sook [Korea University, Seoul (Korea, Republic of)

    2011-02-15

    The anatomy of the left atrium (LA) and the pulmonary veins (PVs) is important in planning and performing successful electrophysiologic ablation (EPA) for atrial fibrillation (Afib) patients. The authors estimated the findings of LA and PVs of Afib patients by MDCT, and compared these with the findings of LA and PVs of the non- Afib group using coronary CT angiography (CCTA). From September, 2009 to February, 2010, 91 Afib patients underwent PVCT (male: female = 72:19, mean age = 55.0-years-old) before EPA. At same time, 90 patients underwent CCTA (male: female = 73:17, mean age = 59.1- years-old). Two radiologists reviewed and analyzed all axial and 3D images of LA and PVs retrospectively with consensus. The average LA volumes of the Afib group(100.49 mm3) was larger than that of the non-Afib group (78.38 mm3) (p<0.05). The average lengths of the LA right wall in the Afib group (40.25 mm) was longer than that of the non-Afib group (37.3 mm) (p<0.05). The average distances between the PV ostium and first segmental bifurcation of the Lt superior PV (LSPV) and the RSPV were shorter in the Afib group (LSPV, 19.38 mm: RSPV, 11.49 mm) than in the non-Afib group (LSPV, 23.23 mm: RSPV, 14.25 mm) (p<0.05). There were higher incidences of anomalous branches such as ostial, accessory branches, or common ostia in the Afib group versus the non-Afib group (p<0.05). In Afib group, variable parameters of LA and PVs were obtained and estimated by MDCT, and there was statistically significant difference in the parameters of LA and PVs between Afib and non-Afib groups

  18. MDCT Evaluation of Left Atrium and Pulmonary Vein in the Patients with Atrial Fibrillation: Comparison with the Non-Atrial Fibrillation Group

    International Nuclear Information System (INIS)

    Kim, Won Jung; Choi, Eun Jeong; Ham, Soo Yeon; Oh, Yu Whan; Kim, Young Hoon; Yong, Hwan Seok; Yang, Kyung Sook

    2011-01-01

    The anatomy of the left atrium (LA) and the pulmonary veins (PVs) is important in planning and performing successful electrophysiologic ablation (EPA) for atrial fibrillation (Afib) patients. The authors estimated the findings of LA and PVs of Afib patients by MDCT, and compared these with the findings of LA and PVs of the non- Afib group using coronary CT angiography (CCTA). From September, 2009 to February, 2010, 91 Afib patients underwent PVCT (male: female = 72:19, mean age = 55.0-years-old) before EPA. At same time, 90 patients underwent CCTA (male: female = 73:17, mean age = 59.1- years-old). Two radiologists reviewed and analyzed all axial and 3D images of LA and PVs retrospectively with consensus. The average LA volumes of the Afib group(100.49 mm3) was larger than that of the non-Afib group (78.38 mm3) (p<0.05). The average lengths of the LA right wall in the Afib group (40.25 mm) was longer than that of the non-Afib group (37.3 mm) (p<0.05). The average distances between the PV ostium and first segmental bifurcation of the Lt superior PV (LSPV) and the RSPV were shorter in the Afib group (LSPV, 19.38 mm: RSPV, 11.49 mm) than in the non-Afib group (LSPV, 23.23 mm: RSPV, 14.25 mm) (p<0.05). There were higher incidences of anomalous branches such as ostial, accessory branches, or common ostia in the Afib group versus the non-Afib group (p<0.05). In Afib group, variable parameters of LA and PVs were obtained and estimated by MDCT, and there was statistically significant difference in the parameters of LA and PVs between Afib and non-Afib groups

  19. Mitral Annulus Myxoma Extending into Left Atrium and Left Ventricle with Severe Mitral Regurgitation as a Pre-Operative Finding, a Rarity

    Directory of Open Access Journals (Sweden)

    Hamza Abdur Rahim Khan

    2017-06-01

    Full Text Available Cardiac tumors constitute 0.2% of all tumors. Primary cardiac tumors occur infrequently with an incidence of 0.0017-0.19% as shown by autopsies performed in non-selected populations. Among these tumors, cardiac myxomas are most commonly encountered, with left atrial myxomas being more prevalent than right atrial ones. The classic triad of symptoms, of which at least one is present in a patient with atrial myxoma, are obstructive traits including dyspnea and syncope, constitutional symptoms such as fever and anorexia, and thromboembolic events. Surgical resection confers almost definitive treatment with recurrence rates being as low as 3%. A 50-year-old woman referred to the Emergency Unit with a sudden episode of chest heaviness and shortness of breath. There was no significant physical examination finding and all routine lab investigations were normal. She underwent an angiography that revealed tight left anterior descending artery stenosis. An angioplasty was also performed, but she had an episode of presyncope immediately. Then, echocardiogram was performed that showed a large left atrial myxoma causing severe mitral regurgitation. Thus, urgent open heart surgery was planned. The myxoma was identified and excised, the mitral annulus resolved, and normal flow was restored. The patient was then discharged home and followed up for 2 months with no complaints. In the current study, we reported a rare case where mitral regurgitation was caused by a left atrial myxoma. Our report highlighted the diverse clinical spectrum of myxoma and emphasized the need for early echocardiographic diagnosis to aid in identification of myxoma followed by early surgical intervention.

  20. The impact of the CartoSound® image directly acquired from the left atrium for integration in atrial fibrillation ablation.

    Science.gov (United States)

    Kaseno, Kenichi; Hisazaki, Kaori; Nakamura, Kohki; Ikeda, Etsuko; Hasegawa, Kanae; Aoyama, Daisetsu; Shiomi, Yuichiro; Ikeda, Hiroyuki; Morishita, Tetsuji; Ishida, Kentaro; Amaya, Naoki; Uzui, Hiroyasu; Tada, Hiroshi

    2018-04-14

    Intracardiac echocardiographic (ICE) imaging might be useful for integrating three-dimensional computed tomographic (CT) images for left atrial (LA) catheter navigation during atrial fibrillation (AF) ablation. However, the optimal CT image integration method using ICE has not been established. This study included 52 AF patients who underwent successful circumferential pulmonary vein isolation (CPVI). In all patients, CT image integration was performed after the CPVI with the following two methods: (1) using ICE images of the LA derived from the right atrium and right ventricular outflow tract (RA-merge) and (2) using ICE images of the LA directly derived from the LA added to the image for the RA-merge (LA-merge). The accuracy of these two methods was assessed by the distances between the integrated CT image and ICE image (ICE-to-CT distance), and between the CT image and actual ablated sites for the CPVI (CT-to-ABL distance). The mean ICE-to-CT distance was comparable between the two methods (RA-merge = 1.6 ± 0.5 mm, LA-merge = 1.7 ± 0.4 mm; p = 0.33). However, the mean CT-to-ABL distance was shorter for the LA-merge (2.1 ± 0.6 mm) than RA-merge (2.5 ± 0.8 mm; p imaging, and whereas the greatest CT-to-ABL distance was observed at the roof portion of the left superior PV (3.7 ± 2.8 mm) after the RA-merge, it improved to 2.6 ± 1.9 mm after the LA-merge (p images of the LA directly acquired from the LA might lead to a greater accuracy of the CT image integration for the CVPI.

  1. Circumferential lesion formation around the pulmonary veins in the left atrium with focused ultrasound using a 2D-array endoesophageal device: a numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Pichardo, Samuel; Hynynen, Kullervo [Imaging Research-Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room C713, Toronto, ON M4N 3M5 (Canada)

    2007-08-21

    Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia affecting humans. The electrical isolation by ablation of the pulmonary veins (PVs) in the left atrium (LA) of the heart has been proven as an effective cure of AF. The ablation consists mainly in the formation of a localized circumferential thermal coagulation of the cardiac tissue surrounding the PVs. In the present numerical study, the feasibility of producing the required circumferential lesion with an endoesophageal ultrasound probe is investigated. The probe operates at 1 MHz and consists of a 2D array with enough elements (114 x 20) to steer the acoustic field electronically in a volume comparable to the LA. Realistic anatomical conditions of the thorax were considered from the segmentation of histological images of the thorax. The cardiac muscle and the blood-filled cavities in the heart were identified and considered in the sound propagation and thermal models. The influence of different conditions of the thermal sinking in the LA chamber was also studied. The circumferential ablation of the PVs was achieved by the sum of individual lesions induced with the proposed device. Different scenarios of lesion formation were considered where ultrasound exposures (1, 2, 5 and 10 s) were combined with maximal peak temperatures (60, 70 and 80 {sup 0}C). The results of this numerical study allowed identifying the limits and best conditions for controlled lesion formation in the LA using the proposed device. A controlled situation for the lesion formation surrounding the PVs was obtained when the targets were located within a distance from the device in the range of 26 {+-} 7 mm. When combined with a maximal temperature of 70 {sup 0}C and an exposure time between 5 and 10 s, this distance ensured preservation of the esophageal structures, controlled lesion formation and delivery of an acoustic intensity at the transducer surface that is compatible with existing materials. With a peak

  2. Three-dimensional rotational angiography of the left atrium and the oesophagus: the short-term mobility of the oesophagus and the stability of the fused three-dimensional model of the left atrium and the oesophagus during catheter ablation for atrial fibrillation.

    Science.gov (United States)

    Starek, Zdenek; Lehar, Frantisek; Jez, Jiri; Scurek, Martin; Wolf, Jiri; Kulik, Tomas; Zbankova, Alena; Novak, Miroslav

    2017-08-01

    The objective of this study was to evaluate the mobility of the oesophagus and the stability of the three-dimensional (3D) model of the oesophagus using 3D rotational angiography (3DRA) of the left atrium (LA) and the oesophagus, fused with live fluoroscopy during catheter ablation for atrial fibrillation. From March 2015 to September 2015, 3DRA of the LA and the oesophagus was performed in 33 patients before catheter ablation for atrial fibrillation. Control contrast oesophagography was performed every 30 min. The positions of the oesophagograms and the 3D model of the LA and the oesophagus were repeatedly measured and compared with the spine. The average shift of the oesophagus ranged from 2.7 ± 2.2 to 5.0 ± 3.5 mm. The average real-time oesophageal shift ranged from 2.7 ± 2.2 to 3.8 ± 3.4 mm. No significant shift was detected until the 90th minute of the procedure. The average shift of the 3D model of the LA and the oesophagus ranged from 1.4 ± 1.8 to 3.3 ± 3.0 mm (right-left direction) and from 0.9 ± 1.2 to 2.2 ± 1.3 mm (craniocaudal direction). During the 2 h procedure, there were no significant shifts of the model. During catheter ablation for atrial fibrillation, there is no significant change in the position of the oesophagus until the 90th minute of the procedure and no significant shift in the 3D model of the LA and the oesophagus. The 3D model of the oesophagus reliably depicts the position of the oesophagus during the entire procedure. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  3. The role of Multidetector CT in the evaluation of the left atrium and pulmonary veins anatomy before and after radio-frequency catheter ablation for atrial fibrillation. Preliminary results and work in progress.Technical note

    International Nuclear Information System (INIS)

    Centoze, Maurizio; Della Sala, Sabino Walter; Dalla Palma, Francesco; Del Greco, Maurizio; Marini, Massimiliano; Nollo, Giandomenico; Ravelli, Flavia

    2005-01-01

    Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins is increasingly being used to treat recurrent or refractory atrial fibrillation that doesn't respond to pharmacologic therapy or cardioversion. Successful RFCA of atrial al fibrillation depends on the pre-procedural understanding of the complex anatomy of the distal pulmonary veins and the left atrium. Aim of this parer is to describe the technical main features that characterise the multidetector helical computed tomography in the evaluation of this anatomic region before and after RFCA procedure. The 3D post-processing techniques useful for pre-RFCA planning are straightforward [it

  4. A cooled intraesophageal balloon to prevent thermal injury during endocardial surgical radiofrequency ablation of the left atrium: a finite element study

    Energy Technology Data Exchange (ETDEWEB)

    Berjano, Enrique J [Center for Research and Innovation on Bioengineering, Valencia Polytechnic University, Camino de Vera s/n, 46022 Valencia (Spain); Hornero, Fernando [Cardiac Surgery Department, Valencia University General Hospital, Avd Tres Cruces s/n, 46014, Valencia (Spain)

    2005-10-21

    Recent clinical studies on intraoperative monopolar radiofrequency ablation of atrial fibrillation have reported some cases of injury to the esophagus. The aim of this study was to perform computer simulations using three-dimensional finite element models in order to investigate the feasibility of a cooled intraesophageal balloon appropriately placed to prevent injury. The models included atrial tissue and a fragment of esophagus and lung linked by connective tissue. The lesion depth in the esophagus was assessed using a 50 deg. C isotherm and expressed as a percentage of thickness of the esophageal wall. The results are as follows: (1) chilling the esophagus by means of a cooled balloon placed in the lumen minimizes the lesion in the esophageal wall compared to the cases in which no balloon is used (a collapsed esophagus) and with a non-cooled balloon; (2) the temperature of the cooling fluid has a more significant effect on the minimization of the lesion than the rate of cooling (the thermal transfer coefficient for forced convection); and (3) pre-cooling periods previous to RF ablation do not represent a significant improvement. Finally, the results also suggest that the use of a cooled balloon could affect the transmurality of the atrial lesion, especially in the cases where the atrium is of considerable thickness. (note)

  5. Antenatal and postnatal sonographic imaging findings of a single ventricle presenting as double outlet right ventricle with rudimentary left ventricle and single atrium

    Directory of Open Access Journals (Sweden)

    Donboklang Lynser

    2015-11-01

    Full Text Available Congenital heart disease is a major cause of morbidity and mortality. Single ventricle is a rare finding and usually of left ventricular morphology. We present here interesting antenatal and postnatal echocardiographic findings of a baby having a rare single ventricle of right ventricular morphology with double outlet. Antenatally we saw a large ventricular septal defect indistinguishable from a single ventricle with left to right ventricular ratio of 1:1. Postnatally we saw a single ventricle having the outlets for both the main pulmonary artery and aortic root. The left ventricle is collapse with a rudimentary morphology possibly due to changes in hemodynamics after birth and absent of outlet from it.

  6. [Effects of 2-(p-dimethylaminostyryl) pyridine methycholide (DSPM-Ci) on ECG, left atrium contractivity and on papillary muscle action potentials].

    Science.gov (United States)

    Jiang, X Y; Zhou, C M; Li, D M; Zhang, K J

    1996-01-01

    The effects of DSPM-Cl on ECG in rats, on the dose-effect curve in guinea pig left atria and on the fast action potential (AP), high-K+ depolarized slow action potential (SAP) in guinea pigs papillary muscle were examined electrophysiologically. DSPM-Cl (2 mg.kg-1) showed significant nagative frequency, negative conductivity effect, and prolonged the PP and PR interval. DSPM-CI (30-50 mumol.L-1) was shown to inhibit left atria contractility and shift the concentration-response curve of Iso and CaCl2 to the right with PD2' values of 4.60 and 4.13, respectively. In addition, DSPM-Cl was found to prolong the duration of action potential 90 (APD90) and effective refractory period (ERP), and decrease the maximal upstroke velocity (Vmax) in K(+)-depolarized guinea pigs papillary muscles. The results suggest that, like verpamil, DSPM-Cl might be a calcium antagonist.

  7. Preferential streaming of the ductus venosus toward the right atrium is associated with a worse outcome despite a higher rate of invasive procedures in human fetuses with left diaphragmatic hernia.

    Science.gov (United States)

    Stressig, R; Fimmers, R; Schaible, T; Degenhardt, J; Axt-Fliedner, R; Gembruch, U; Kohl, T

    2013-12-01

    Preferential streaming of the ductus venosus (DV) toward the right atrium has been observed in fetuses with left diaphragmatic hernia (LDH). The purpose of this retrospective study was to compare survival rates to discharge between a group with preferential streaming of the DV toward the right heart and a group in which this abnormal flow pattern was not present. We retrospectively searched our patient records for fetuses with LDH in whom liver position, DV streaming and postnatal outcome information was available. 55 cases were found and divided into two groups: Group I fetuses exhibited abnormal DV streaming toward the right side of the heart; group II fetuses did not. Various prognostic and outcome parameters were compared. 62 % of group I fetuses and 88 % of group II fetuses survived to discharge (p = 0.032). Fetoscopic tracheal balloon occlusion (FETO) was performed in 66 % of group I fetuses and 23 % of group II fetuses (p = 0.003). Postnatal ECMO therapy was performed in 55 % of group I fetuses and 23 % of group II infants (p = 0.025). Moderate to severe chronic lung disease in survivors was observed in 56 % of the survivors of group I and 9 % of the survivors of group II (p = 0.002). Preferential streaming of the DV toward the right heart in human fetuses with left-sided diaphragmatic hernia was associated with a poorer postnatal outcome despite a higher rate of invasive pre- and postnatal procedures compared to fetuses without this flow abnormality. Specifically, abnormal DV streaming was found to be an independent predictor for FETO. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Resección de un carcinoma renal izquierdo con extensión trombótica hacia la aurícula derecha Resection of a left renal carcinoma with thrombotic extension to right atrium

    Directory of Open Access Journals (Sweden)

    Alejandro Villar Inclán

    2010-09-01

    Full Text Available Se presenta el caso de un hombre de 59 años con diagnóstico de hipernefroma izquierdo y trombosis de la vena cava inferior con extensión hacia la aurícula derecha. Un equipo multidisciplinario realizó una nefrectomía radical izquierda, exposición de la vena cava inferior con técnica de piggyback, atriotomía derecha y cavotomía inferior para extracción del trombo, previo pinzamiento de la vena renal derecha y el hilio hepático. El tiempo quirúrgico total fue de 7 h 30 min. El procedimiento se realizó con anestesia general y un período mínimo de derivación cardiopulmonar. Se utilizó monitorización transoperatoria estandarizada de los parámetros vitales y además ecocardiografía transesofágica para la detección de la remoción completa del trombo y su extracción, así como posibles émbolos desprendidos. La evolución transoperatoria y posoperatoria fue satisfactoria. Se realiza una revisión de la literatura médica internacional sobre el tema y se ofrecen conclusiones.This is the male case aged 59 diagnosed with left hypernephroma and thrombosis of the inferior vena cava with extension to right atrium. A multidisciplinary staff performed a left radical nephrectomy, exposition of inferior vena cava using the piggyback technique, right atriotomy and inferior cavotomy for extension of thrombus and previous clamping of right renal vein and hepatic hilus. The total surgical time was of 7 hours and 30 minutes. The procedure was performed under general anesthesia and a minimal period of cardiopulmonary shunt. Standardized transoperative monitoring of vital parameters was used and also transesophageal echocardiography to detect the total removal of thrombus and its extraction, as well as the potential detached emboli. The transoperative and postoperative course was satisfactory. A review of the international medical literature on this subject was made offering conclusions.

  9. Acesso transeptal vertical ampliado em reoperações valvares mitrais com átrio esquerdo pequeno Extended vertical transseptal approach in mitral valve reoperation with a small left atrium

    Directory of Open Access Journals (Sweden)

    Walter Vosgrau Fagundes

    2004-03-01

    Full Text Available OBJETIVO: Avaliar a abordagem transeptal vertical ampliada em reoperações da valva mitral com átrio esquerdo pequeno. MÉTODO: De janeiro de 2001 a dezembro de 2002, 15 pacientes portadores de doença valvar mitral com indicação de reintervenção cirúrgica, átrio esquerdo pequeno (menor ou igual a 4,0 cm e fibrilação atrial crônica, foram submetidos à abordagem transeptal vertical ampliada da valva mitral. Nove pacientes (pt eram do sexo feminino. A idade variou de 22 a 48 anos. As indicações cirúrgicas foram: disfunção de prótese mitral (seis pt; insuficiência mitral (cinco pt e dupla lesão mitral (quatro pt. Três pacientes apresentavam insuficiência aórtica associada e um pt, insuficiência tricúspide. Nove (60% pacientes encontravam-se em ICC CF III da NYHA e seis (40%, em CF IV. RESULTADOS: A exposição do aparelho valvar mitral foi excelente. O tempo de circulação extracorpórea variou de 65 a 150 min (média = 95min. Foram implantadas próteses em todos os pacientes (15 mitrais, três aórticas e um tricúspide. A mortalidade hospitalar foi de 6,7%, com um óbito devido a baixo débito cardíaco e falência de múltiplos órgãos. Um (6,7% paciente apresentou broncopneumonia na fase hospitalar. Dez pacientes permaneceram com fibrilação atrial, três pt reverteram para ritmo sinusal e um evoluiu com ritmo juncional. A permanência hospitalar média foi de 8,2 dias. Doze (85,7% pacientes encontram-se em CF I e dois (14,3% em CF II. A curva atuarial de sobrevida é de 92,5 % em 22 meses de seguimento. CONCLUSÃO: A técnica cirúrgica empregada proporciona excelente visibilização do aparelho valvar mitral, com baixo índice de complicações.OBJECTIVE: To evaluate the efficacy of the extended vertical transseptal approach in mitral valve reoperation with a small left atrium. METHOD: From January 2001 to December 2002, 15 patients with previous mitral operations, small left atrium and atrial fibrillation

  10. Anomalía del retorno venoso sistémico Drenaje anómalo de la vena cava superior derecha a la aurícula izquierda: Revisión de la literatura y reporte de caso Anomalous systemic venous return. Anomalous drainage of the right superior vena cava into the left atrium: Review of literature and case report

    Directory of Open Access Journals (Sweden)

    Ríos Giovanny

    2012-06-01

    Full Text Available La anomalía total del retorno venoso sistémico tiene gran variedad de presentaciones; sin embargo, la patología de más baja frecuencia es el drenaje de vena cava superior derecha a la aurícula izquierda, hecho de peso para que en el mundo se reporten pocos casos. En la Fundación Clínica Abood Shaio se trató el caso de una paciente de seis años de edad con drenaje venoso total de cava superior derecha a la aurícula izquierda, mediante la técnica de movilización de cava superior y anastomosis cavo-atrial, y se obtuvieron buenos resultados. El caso es mención corresponde al número 21 en la literatura mundial.Total anomalous systemic venous return has a variety of presentations, being the drainage of right superior vena cava into the left atrium a low frequency condition. There are few reported cases in the world. In Shaio Clinic Foundation we have handled a case of total venous drainage of the right superior vena cava into the left atrium in a 6-year old girl, using the superior vena cava mobilization technique and cavo-atrial anastomosis, with good results. This case is reported as case number 21 in the world.

  11. PLA Missions Beyond Taiwan

    National Research Council Canada - National Science Library

    Miller, Marc

    2008-01-01

    KEY INSIGHTS: *The PLA is being assigned and training for an increasing variety of missions, including nontraditional battlefields such as outer space and cyber space, as well as nontraditional functions...

  12. Pla(y)ceskabelse

    DEFF Research Database (Denmark)

    Toft, Herdis; Nørgård, Rikke Toft

    2015-01-01

    pla(y)ceskabelse, transgression, det legekulturelle: "Hvad nu hvis...?" og det konstruktionistisk-designrettede "Hvordan kan vi...?" forstærker opmærksomheden over for læringspotentialer i leg som designvirksomhed. I en interdisciplinær analysemodel tilkobles desuden begreber for modularitet......, flytbarhed, idégenerering, problemløsning, åbenhed og tilblivelse til indfangning af design- og læringspotentialer i legende børns interaktioner med robotteknologier. Artiklen konkluderer, at mødet mellem legebørn og robotteknologi, konceptualiseret som pla(y)ceskabelse, fremmer børns erobring af...

  13. Spectroscopic photoacoustic imaging of radiofrequency ablation in the left atrium

    NARCIS (Netherlands)

    S. Iskander-Rizk (Sophinese); P. Kruizinga (Pieter); A.F.W. van der Steen (Ton); G. van Soest (Gijs)

    2018-01-01

    textabstractCatheter-based radiofrequency ablation for atrial fibrillation has long-term success in 60-70% of cases. A better assessment of lesion quality, depth, and continuity could improve the procedure’s outcome. We investigate here photoacoustic contrast between ablated and healthy atrial-wall

  14. New Engineering Principles in Atrium Smoke Management

    DEFF Research Database (Denmark)

    Valkvist, Morten Birk Sabroe

    A typical atrium smoke management setup was divided into characteristic flow regions; axisymmetric plume, ceiling jet/approach flow, rotation region and spill plume. A grid convergence study was conducted on each of the flow regions in order to determine the non-dimensional grid resolution required...

  15. Investigating atrium in hot and humid climate and providing ...

    African Journals Online (AJOL)

    Atrium has thermal comfort space since the old time by two methods of greenhouse effect and chimney effect. Now these questions are raised: What impact does atrium have in terms of performance in reducing energy consumption in buildings and how is the performance of atrium in the hot and humid climate, and how it ...

  16. Synthesis and application of PLA and PLA/GO fibers through thermo-responsive transformation of PLA particles

    OpenAIRE

    Bolakhrif, Sabah

    2016-01-01

    PLA nanofibers were successively produced by thermo-responsive transformation of PLA particles in water. The morphological structure of the nanofibers could be optimized by the heat treatment as well as the incorporation of GO to the fiber surface. PLA/GO fiber demonstrated a more stable morphology and GO provided good compatibility between PLA and starch. Both PLA and PLA/GO fibers incorporated in starch films resulted in increased thermal stability and mechanical properties. However, the mo...

  17. Increased FDG uptake in the wall of the right atrium in people who participated in a cancer screening program with whole-body PET

    International Nuclear Information System (INIS)

    Fujii, Hirofumi; Ide, Michiru; Yasuda, Seiei; Takahashi, Wakoh; Shohtsu, Akira; Kubo, Atsushi

    1999-01-01

    The purpose of this study was to evaluate the characteristics of patients who showed increased FDG uptake in the wall of the right atrium. We have encountered 10 patients with increased activity in the wall of the right atrium among a total of 2,367 examinees who participated in our cancer screening program with whole-body PET. The mean age of these examinees was 62.9 yr, higher than that of the total population. All suffered from cardiac disorders, especially atrial fibrillation. FDG accumulated almost exclusively in the wall of the right atrium, whereas only slight activity was seen in the wall of the left atrium. Although the average size of the right atria was significantly enlarged, left atria were more severely dilated than right ones. Therefore overload does not seem to account for the FDG accumulation in the wall of the right atrium. In conclusion, the increased activity in the wall of the right atrium was a rare finding that was made in older people who suffered from cardiac disease. Although the mechanism of induction of the high metabolic state of glucose in the wall of the right atrium remains unclear, this unusual activity would be another false positive finding in cancer screening with whole-body FDG PET. (author)

  18. sPLA2-IIA

    Indian Academy of Sciences (India)

    67

    Recent research showed that maslinic acid interacts with sPLA2-IIA ... Further analysis revealed that sPLA2-IIA only induced modest LDL ..... MDA/mg protein) compared to native LDL (2.043 nmol MDA/mg protein) while .... to modify extracellular non-cellular lipid components such as lipoproteins, ... The main pathway for.

  19. The role of Multidetector CT in the evaluation of the left atrium and pulmonary veins anatomy before and after radio-frequency catheter ablation for atrial fibrillation. Preliminary results and work in progress.Technical note; Il ruolo della TC Multidetettore nella valutazione anatomica dell'atrio sinistro e delle vene polmonari prima e dopo ablazione percutanea con radiofrequenza della fibrillazione atriale. Risultati preliminari e work in progress

    Energy Technology Data Exchange (ETDEWEB)

    Centoze, Maurizio; Della Sala, Sabino Walter; Dalla Palma, Francesco [Azienda Provinciale per i servizi sanitari, Trento (Italy). Dipartimento di radiodiagnostica; Del Greco, Maurizio; Marini, Massimiliano [Ospedale S. Chiara, Trento (Italy). U.O. di cardiologia; Nollo, Giandomenico; Ravelli, Flavia [Trento Univ., Trento (Italy). Dipartimento di fisica

    2005-07-15

    Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins is increasingly being used to treat recurrent or refractory atrial fibrillation that doesn't respond to pharmacologic therapy or cardioversion. Successful RFCA of atrial al fibrillation depends on the pre-procedural understanding of the complex anatomy of the distal pulmonary veins and the left atrium. Aim of this parer is to describe the technical main features that characterise the multidetector helical computed tomography in the evaluation of this anatomic region before and after RFCA procedure. The 3D post-processing techniques useful for pre-RFCA planning are straightforward. [Italian] La ablazione percutanea con radiofrequenza (RFCA) del tratto distale delle vene polmonari nella fibrillazione atriale, che non risponde al trattamento farmacologico e alla cardioversione elettrica, e una procedura in grande sviluppo. Il successo del trattamento dipende dalla comprensione della complessa anatomia delle vene polmonari e dell'atrio sinistro. Lo scopo di questo articolo e illustrare gli aspetti tecnici fondamentali che caratterizzano lo studio di questa regione anatomica con TC spirale multidetettore prima e dopo RFCA. Particolare risalto e stato rivolto alle tecniche di post-processing 3D estremamente utili nella pianificazione della procedura di ablazione.

  20. Beoordeling RWA-installatie Atrium Vertigo: Rookverspreiding door het gebouw

    NARCIS (Netherlands)

    Neuhaus, E.

    2004-01-01

    Het atrium van het Vertigo-gebouw is bouwkundig bedoeld als één groot brandcompartiment. De schuifdeuren en ramen naar aanliggende vertrekken staan echter vaak open. Hierdoor kan de rook zich in het geval van een brand in het atrium gemakkelijk door het gebouw verspreiden door een overdruk in het

  1. Resectable hepatoblastoma with tumor thrombus extending into the right atrium after chemotherapy: A case report

    Directory of Open Access Journals (Sweden)

    Kosuke Endo

    2016-04-01

    Full Text Available Hepatoblastoma with intraatrial tumor thrombus is relatively rare. We report a case of hepatoblastoma with tumor thrombus extending into the right atrium, which responded well to chemotherapy and was resected using extracorporeal circulation. A 4-year-old girl was referred to our hospital because of abdominal distention and tenderness. A computed tomography (CT scan showed a large tumor occupying the left 3 segments of the liver with tumor thrombus extending into the right atrium. There was also a small intrahepatic metastasis in the right lobe of the liver. She was diagnosed with hepatoblastoma on the basis of the results of open biopsy. Neoadjuvant chemotherapy with an intense CDDP-based regimen was performed. The tumor responded well to chemotherapy, and intrahepatic metastasis became undetectable on CT scan, although the tumor thrombus remained in the right atrium. After 7 courses of chemotherapy, we performed resection using extracorporeal circulation. The postoperative course was uneventful, and adjuvant chemotherapy was started 10 days after the operation. Her serum alpha-fetoprotein (AFP level decreased to the normal range, and she was free of disease for 1 year after the operation. Tumor resection using extracorporeal circulation can be performed safely and is justified in patients with intraatrial tumor thrombus.

  2. Creating a Positive PLA Experience: A Step-by-Step Look at University PLA

    Science.gov (United States)

    Leiste, Sara M.; Jensen, Kathryn

    2011-01-01

    A prior learning assessment (PLA) can be an intimidating process for adult learners. Capella University's PLA team has developed best practices, resources, and tools to foster a positive experience and to remove barriers in PLA and uses three criteria to determine how to best administer the assessment. First, a PLA must be motivating, as described…

  3. Case Report: Giant Right Atrium in Rheumatic Mitral Disease

    Directory of Open Access Journals (Sweden)

    Deniz Demir

    2014-06-01

    Full Text Available Dilation and hypertrophy of the atria occur in patients with valvular heart disease especially in mitral regurgitation, mitral stenosis or tricuspid abnormalities. Dilatation of the atriums which occurs slowly in time, becomes evident with ritim disturbances and embolic events. We report a case of an unusual giant right atrium in context of rheumatic mitral stenosis, mitral regurgitation, pulmonar hypertansion and severe tricuspid regurgitation in a 40-year-old man who underwent succesfull operations as mitral valve replacement, Maze-IV radiofrequency ablation, right atrium atrioplasty and De Vega anuloplasty. [J Contemp Med 2014; 4(2.000: 98-102

  4. Dataset on the energy performance of atrium type hotel buildings.

    Science.gov (United States)

    Vujosevic, Milica; Krstic-Furundzic, Aleksandra

    2018-04-01

    The data presented in this article are related to the research article entitled "The Influence of Atrium on Energy Performance of Hotel Building" (Vujosevic and Krstic-Furundzic, 2017) [1], which describes the annual energy performance of atrium type hotel building in Belgrade climate conditions, with the objective to present the impact of the atrium on the hotel building's energy demands for space heating and cooling. This dataset is made publicly available to show energy performance of selected hotel design alternatives, in order to enable extended analyzes of these data for other researchers.

  5. Inflammatory Myofibroblastic Tumor of the Right Atrium

    Directory of Open Access Journals (Sweden)

    Neerod K. Jha

    2010-01-01

    Full Text Available Cardiac inflammatory myofibroblastic tumor (IMT is a rare entity and is associated with distinct clinical, pathological and molecular features. The clinical behavior, natural history, biological potential, management and prognosis of such tumors are unclear. We present herewith an adolescent girl who presented with similar entity involving the junction of the right atrium and the inferior vena cava (IVC in association with thrombocytosis and IVC thrombosis leading to obstruction of blood flow. Diagnostic tools included imaging and immuno-histopathology studies. Surgical management included resection of the tumor and thrombo-embolectomy of the IVC under cardiopulmonary bypass. This case is unique due to association of complete obstruction of IVC caused by the strategic location of the tumor, thrombosis of vena cava and association of thrombocytosis. These features have not been reported yet in relation to the cardiac IMT. This report will help in better understanding and management of similar cases in terms of planning cannulation of femoral veins or application of total hypothermic circulatory arrest during cardiopulmonary bypass and prompt us to look for recurrence or metastasis during follow up using echocardiography and laboratory investigations. The possibility of IMT should be kept in the differential diagnosis of cardiac tumors especially in children and adolescents.

  6. Left Atrial Decompression by Percutaneous Left Atrial Venting Cannula Insertion during Venoarterial Extracorporeal Membrane Oxygenation Support

    Directory of Open Access Journals (Sweden)

    Ha Eun Kim

    2016-06-01

    Full Text Available Patients with venoarterial extracorporeal membrane oxygenation (ECMO frequently suffer from pulmonary edema due to left ventricular dysfunction that accompanies left heart dilatation, which is caused by left atrial hypertension. The problem can be resolved by left atrium (LA decompression. We performed a successful percutaneous LA decompression with an atrial septostomy and placement of an LA venting cannula in a 38-month-old child treated with venoarterial ECMO for acute myocarditis.

  7. Analysis of Several PLA2 mRNA in Human Meningiomas

    OpenAIRE

    Denizot, Yves; De Armas, Rafael; Durand, Karine; Robert, Sandrine; Moreau, Jean-Jacques; Caire, Fran?ois; Weinbreck, Nicolas; Labrousse, Fran?ois

    2010-01-01

    In view of the important oncogenic action of phospholipase A2(PLA2) we investigated PLA2 transcripts in human meningiomas. Real-time PCR was used to investigate PLA2 transcripts in 26 human meningioma tumors. Results indicated that three Ca2+-dependent high molecular weight PLA2 (PLA2-IVA, PLA2-IVB, PLA2-IVC), one Ca2+-independent high molecular weight PLA2 (PLA2-VI) and five low molecular weight secreted forms of PLA2 (PLA2-IB, PLA2-IIA, PLA2-III, PLA2-V, and PLA2-XII) are expressed with PLA...

  8. PLA recycling by hydrolysis at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cristina, Annesini Maria; Rosaria, Augelletti; Sara, Frattari, E-mail: sara.frattari@uniroma1.it; Fausto, Gironi [Department of Chemical Engineering Materials Environment, University of Rome “La Sapienza”, Via Eudossiana 18– 00184 Roma (Italy)

    2016-05-18

    In this work the process of PLA hydrolysis at high temperature was studied, in order to evaluate the possibility of chemical recycling of this polymer bio-based. In particular, the possibility to obtain the monomer of lactic acid from PLA degradation was investigated. The results of some preliminary tests, performed in a laboratory batch reactor at high temperature, are presented: the experimental results show that the complete degradation of PLA can be obtained in relatively low reaction times.

  9. Strong synergistic effects in PLA/PCL blends: Impact of PLA matrix viscosity.

    Science.gov (United States)

    Ostafinska, Aleksandra; Fortelný, Ivan; Hodan, Jiří; Krejčíková, Sabina; Nevoralová, Martina; Kredatusová, Jana; Kruliš, Zdeněk; Kotek, Jiří; Šlouf, Miroslav

    2017-05-01

    Blends of two biodegradable polymers, poly(lactic acid) (PLA) and poly(ϵ-caprolactone) (PCL), with strong synergistic improvement in mechanical performance were prepared by melt-mixing using the optimized composition (80/20) and the optimized preparation procedure (a melt-mixing followed by a compression molding) according to our previous study. Three different PLA polymers were employed, whose viscosity decreased in the following order: PLC ≈ PLA1 > PLA2 > PLA3. The blends with the highest viscosity matrix (PLA1/PCL) exhibited the smallest PCL particles (d∼0.6μm), an elastic-plastic stable fracture (as determined from instrumented impact testing) and the strongest synergistic improvement in toughness (>16× with respect to pure PLA, exceeding even the toughness of pure PCL). According to the available literature, this was the highest toughness improvement in non-compatiblized PLA/PCL blends ever achieved. The decrease in the matrix viscosity resulted in an increase in the average PCL particle size and a dramatic decrease in the overall toughness: the completely stable fracture (for PLA1/PCL) changed to the stable fracture followed by unstable crack propagation (for PLA2/PCL) and finally to the completely brittle fracture (for PLA3/PCL). The stiffness of all blends remained at well acceptable level, slightly above the theoretical predictions based on the equivalent box model. Despite several previous studies, the results confirmed that PLA and PCL could behave as compatible polymers, but the final PLA/PCL toughness is extremely sensitive to the PCL particle size distribution, which is influenced by both processing conditions and PLA viscosity. PLA/PCL blends with high stiffness (due to PLA) and toughness (due to PCL) are very promising materials for medical applications, namely for the bone tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Thermal and mechanical properties of PLA and PBAT/PLA systems; Propriedades mecanicas e termicas de sistemas de PLA e PBAT/PLA

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.C.; Oliveira, S.V. de; Araujo, E.M., E-mail: milecost@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2014-07-01

    Searches with biodegradable materials have grown every day, because they present a lower environmental impact compared to conventional polymers. In this work, biodegradable polymer matrices such as polylactide (PLA) and a poly(adipate butyleneco- terephthalate)/polylactide (PBAT/PLA) blend commercially known as Ecovio ® were used. It was also used a smectite clay from the Paraiba. It was modified with Praepagen surfactant and named as organoclay (OMMT). PLA and PBAT/PLA systems were prepared with organoclay in concentration of 3 wt.%. Initially, masters were produced in a high shear mixer. Subsequently, they were dispersed in the polymer matrix in a do-rotational twin screw extruder. The PLA/OMMT and PBAT/PLA/OMMT biocomposites were characterized by X-ray diffraction (XRD), tensile and impact mechanical properties and Differential Scanning Calorimetry (DSC). According to XRD patterns of PLA/OMMT and PBAT/PLA/OMMT systems, it was observed a probable formation of a microcomposite for both systems. It was noticed that they showed reduction in tensile mechanical properties, however there was an increase in impact strength for PLA/OMMT system. The DSC curves practically no change in the crystallinity of the systems. (author)

  11. PLA composites: From production to properties.

    Science.gov (United States)

    Murariu, Marius; Dubois, Philippe

    2016-12-15

    Poly(lactic acid) or polylactide (PLA), a biodegradable polyester produced from renewable resources, is used for various applications (biomedical, packaging, textile fibers and technical items). Due to its inherent properties, PLA has a key-position in the market of biopolymers, being one of the most promising candidates for further developments. Unfortunately, PLA suffers from some shortcomings, whereas for the different applications specific end-use properties are required. Therefore, the addition of reinforcing fibers, micro- and/or nanofillers, and selected additives within PLA matrix is considered as a powerful method for obtaining specific end-use characteristics and major improvements of properties. This review highlights recent developments, current results and trends in the field of composites based on PLA. It presents the main advances in PLA properties and reports selected results in relation to the preparation and characterization of the most representative PLA composites. To illustrate the possibility to design the properties of composites, a section is devoted to the production and characterization of innovative PLA-based products filled with thermally-treated calcium sulfate, a by-product from the lactic acid production process. Moreover, are emphasized the last tendencies strongly evidenced in the case of PLA, i.e., the high interest to diversify its uses by moving from biomedical and packaging (biodegradation properties, "disposables") to technical applications ("durables"). Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Daylighting in linear atrium buildings at high latitudes

    Energy Technology Data Exchange (ETDEWEB)

    Matusiak, Barbara

    1998-12-31

    This thesis proposes new criteria for visual comfort based on knowledge of visual perception and a method for estimating the modelling ability of light by using inter-reflection calculations. Simplified calculations are presented for the daylight factor in linear building structures, using the projected solid angle principle, for uniform sky and for CIE overcast sky conditions. The calculations are compared with experimental results. Simple diagrams are created based on calculations of the mean daylight factor in rooms adjacent to a narrow street. These diagrams and presented formulas and tables can be used as a simple design tool. Daylighting strategies for linear atrium buildings at high latitudes are developed and examined. These strategies are divided into three groups: (1) the atrium space and facades as light conductor/reflector, (2) the glass roof as a light conductor, and (3) light reflectors on the neighbouring roof. The atrium space and facade strategies are subdivided into passive and active. The strategies connected to the glazed roof includes different configurations of glazing: horizontal, single pitched, double pitched, and the use of laser cut panels and prismatic panels in the glazed roof. The shapes of reflectors on the neighbouring roof are a flat reflector, a parabolic reflector and a parabolic concentrator. Strategies from all three groups are examined on a physical model of scale 1:20 in the artificial sky of mirror box type. Simulations with artificial sun have also been done. The results from model studies are compared with computer simulations. All the active daylighting systems designed for use in the atrium space or on the atrium facades have a huge potential for use in atrium buildings. From the strategies connected with the glazed roof the negatively sloped glass is found to be the best alternative for glazed roofs at high latitudes. Among the roof reflectors, the flat one performs best. 82 refs., 122 figs., 27 tabs.

  13. Massively dilated right atrium masquerading as a mediastinal tumor

    Directory of Open Access Journals (Sweden)

    Thomas Schroeter

    2011-04-01

    Full Text Available Severe tricuspid valve insufficiency causes right atrial dilatation, venous congestion, and reduced atrial contractility, and may eventually lead to right heart failure. We report a case of a patient with severe tricuspid valve insufficiency, right heart failure, and a massively dilated right atrium. The enormously dilated atrium compressed the right lung, resulting in a radiographic appearance of a mediastinal tumor. Tricuspid valve repair and reduction of the right atrium was performed. Follow up examination revealed improvement of liver function, reduced peripheral edema and improved New York Heart Association (NYHA class. The reduction of the atrial size and repair of the tricuspid valve resulted in a restoration of the conduit and reservoir function of the right atrium. Given the chronicity of the disease process and the long-standing atrial fibrillation, there is no impact of this operation on right atrial contraction. In combination with the reconstruction of the tricuspid valve, the reduction atrioplasty will reduce the risk of thrombembolic events and preserve the right ventricular function.

  14. PLA micro- and nano-particles.

    Science.gov (United States)

    Lee, Byung Kook; Yun, Yeonhee; Park, Kinam

    2016-12-15

    Poly(d,l-lactic acid) (PLA) has been widely used for various biomedical applications for its biodegradable, biocompatible, and nontoxic properties. Various methods, such as emulsion, salting out, and precipitation, have been used to make better PLA micro- and nano-particle formulations. They are widely used as controlled drug delivery systems of therapeutic molecules, including proteins, genes, vaccines, and anticancer drugs. Even though PLA-based particles have challenges to overcome, such as low drug loading capacity, low encapsulation efficiency, and terminal sterilization, continuous innovations in particulate formulations will lead to development of clinically useful formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Additive Manufacturing of PLA and CF/PLA Binding Layer Specimens via Fused Deposition Modeling

    Science.gov (United States)

    Li, Yuhang; Gao, Shiyou; Dong, Rongmei; Ding, Xuebing; Duan, Xiaoxi

    2018-02-01

    As one of the most popular additive manufacturing techniques, fused deposition modeling (FDM) is successfully applied in aerospace, automotive, architecture, and other fields to fabricate thermoplastic parts. Unfortunately, as a result of the limited nature of the mechanical properties and mass in raw materials, there is a pressing need to improve mechanical properties and reduce weight for FDM parts. Therefore, this paper presents an experiment of a special polylactic acid (PLA) and carbon fiber (CF)/PLA-laminated experimental specimen fabricated using the FDM process. The mechanical properties and mass analysis of the new composites for the PLA and CF/PLA binding layer specimen are investigated experimentally. Through the experimental analysis, one can conclude that the mass of laminated specimen is lighter than the CF/PLA specimen, and the tensile and flexural mechanical properties are higher than the pure PLA specimen.

  16. Atrial fibrillation: effects beyond the atrium?

    Science.gov (United States)

    Wijesurendra, Rohan S; Casadei, Barbara

    2015-03-01

    Atrial fibrillation (AF) is the most common sustained clinical arrhythmia and is associated with significant morbidity, mostly secondary to heart failure and stroke, and an estimated two-fold increase in premature death. Efforts to increase our understanding of AF and its complications have focused on unravelling the mechanisms of electrical and structural remodelling of the atrial myocardium. Yet, it is increasingly recognized that AF is more than an atrial disease, being associated with systemic inflammation, endothelial dysfunction, and adverse effects on the structure and function of the left ventricular myocardium that may be prognostically important. Here, we review the molecular and in vivo evidence that underpins current knowledge regarding the effects of human or experimental AF on the ventricular myocardium. Potential mechanisms are explored including diffuse ventricular fibrosis, focal myocardial scarring, and impaired myocardial perfusion and perfusion reserve. The complex relationship between AF, systemic inflammation, as well as endothelial/microvascular dysfunction and the effects of AF on ventricular calcium handling and oxidative stress are also addressed. Finally, consideration is given to the clinical implications of these observations and concepts, with particular reference to rate vs. rhythm control. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

  17. Thermal and mechanical properties of PLA and PBAT/PLA systems

    International Nuclear Information System (INIS)

    Silva, M.C.; Oliveira, S.V. de; Araujo, E.M.

    2014-01-01

    Searches with biodegradable materials have grown every day, because they present a lower environmental impact compared to conventional polymers. In this work, biodegradable polymer matrices such as polylactide (PLA) and a poly(adipate butyleneco- terephthalate)/polylactide (PBAT/PLA) blend commercially known as Ecovio ® were used. It was also used a smectite clay from the Paraiba. It was modified with Praepagen surfactant and named as organoclay (OMMT). PLA and PBAT/PLA systems were prepared with organoclay in concentration of 3 wt.%. Initially, masters were produced in a high shear mixer. Subsequently, they were dispersed in the polymer matrix in a do-rotational twin screw extruder. The PLA/OMMT and PBAT/PLA/OMMT biocomposites were characterized by X-ray diffraction (XRD), tensile and impact mechanical properties and Differential Scanning Calorimetry (DSC). According to XRD patterns of PLA/OMMT and PBAT/PLA/OMMT systems, it was observed a probable formation of a microcomposite for both systems. It was noticed that they showed reduction in tensile mechanical properties, however there was an increase in impact strength for PLA/OMMT system. The DSC curves practically no change in the crystallinity of the systems. (author)

  18. Stereocomplex mediated gelation of PEG-(PLA)2 and PEG(PLA)8 block copolymers

    NARCIS (Netherlands)

    Hiemstra, C.; Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan

    2005-01-01

    Stereocomplex mediated hydrogels have been prepared by mixing solutions of polymers of opposite chirality of either PEG-(PLA)2 triblock copolymers or PEG-(PLA)8 star block copolymers. The critical gel concentrations of the mixed enantiomer solutions were considerably lower compared to polymer

  19. Total anomalous systemic venous drainage in left heterotaxy syndrome.

    Science.gov (United States)

    Khandenahally, Ravindranath S; Deora, Surender; Math, Ravi S

    2013-04-01

    Total anomalous systemic venous drainage is an extremely rare congenital heart defect. In this study we describe an 11-year-old girl who presented with a history of fatigue and central cyanosis that she had had since early childhood with unremarkable precordial examination results. Investigations revealed left heterotaxy with all systemic venous drainage to the left-sided atrium with non-compaction of the left ventricle.

  20. Simulation of left atrial function using a multi-scale model of the cardiovascular system.

    Directory of Open Access Journals (Sweden)

    Antoine Pironet

    Full Text Available During a full cardiac cycle, the left atrium successively behaves as a reservoir, a conduit and a pump. This complex behavior makes it unrealistic to apply the time-varying elastance theory to characterize the left atrium, first, because this theory has known limitations, and second, because it is still uncertain whether the load independence hypothesis holds. In this study, we aim to bypass this uncertainty by relying on another kind of mathematical model of the cardiac chambers. In the present work, we describe both the left atrium and the left ventricle with a multi-scale model. The multi-scale property of this model comes from the fact that pressure inside a cardiac chamber is derived from a model of the sarcomere behavior. Macroscopic model parameters are identified from reference dog hemodynamic data. The multi-scale model of the cardiovascular system including the left atrium is then simulated to show that the physiological roles of the left atrium are correctly reproduced. This include a biphasic pressure wave and an eight-shaped pressure-volume loop. We also test the validity of our model in non basal conditions by reproducing a preload reduction experiment by inferior vena cava occlusion with the model. We compute the variation of eight indices before and after this experiment and obtain the same variation as experimentally observed for seven out of the eight indices. In summary, the multi-scale mathematical model presented in this work is able to correctly account for the three roles of the left atrium and also exhibits a realistic left atrial pressure-volume loop. Furthermore, the model has been previously presented and validated for the left ventricle. This makes it a proper alternative to the time-varying elastance theory if the focus is set on precisely representing the left atrial and left ventricular behaviors.

  1. Properties of PET/PLA Electrospun Blends

    Science.gov (United States)

    Li, Kevin; Cebe, Peggy

    2012-02-01

    Electrospun membranes were fabricated from poly(ethylene terephthalate), PET, co-spun with poly(lactic acid), PLA. The PLA contained 2% of the D-isomer, which served to limit the overall degree of crystallinity. Membranes were deposited from blended solutions of PET/PLA in hexafluoroisopropanol. The PET/PLA composition ranged from 0/100, 75/25, 50/50, 25/75, and 100/0. Electrospun membranes were made using either a static flat plate or a rotating wheel as the counter electrode, yielding unoriented mats or highly oriented tapes, respectively. We report on our investigation of the crystallinity, crystal perfection, and mechanical properties of these materials using differential scanning calorimetry, wide and small angle X-ray scattering, and dynamic mechanical analysis. In particular, we study the ability of one blend component (PET) to crystallize in the presence of existing crystals of the second blend component (PLA) which crystallizes first and at a lower temperature than PET.

  2. Is the Chinese Army the Real Winner in PLA Reforms

    Science.gov (United States)

    2016-10-01

    44 Commentary / The Chinese Army and PLA Reforms JFQ 83, 4th Quarter 2016 Is the Chinese Army the Real Winner in PLA Reforms? By Phillip C. Saunders...and John Chen G round force officers run China’s military, the People’s Liberation Army ( PLA ). About 70 percent of PLA soldiers serve in the PLA ...Saunders and Chen 45 services and arms of the PLA ” has meant reductions in “technologically backward” PLAA units and personnel increases for the other

  3. EXAMINATION OF ELECTROPHYSIOLOGICAL PARAMETERS OF THE ATRIUMS IN PATIENTS WITH LONG-TERM PERSISTENT FORM OF ATRIAL FIBRILLATION AND VALVULAR HEART DISEASE

    Directory of Open Access Journals (Sweden)

    A. A. Kulikov

    2017-01-01

    Full Text Available The study objective is to examine electrophysiological parameters of atrial myocardium, characteristics of atrioventricular conduction, and potential factors affecting recurrent atrial fibrillation (AF in patients with persistent and long-term persistent forms of AF prior to the Labirynth IIIB surgery with single-step correction of valvular heart disease.Materials and methods. The study included 100 adults (48 men, 52 women with persistent and long-term persistent forms of AF and different valvular heart diseases. Mean patient age was 59 years. Mean AF duration was 4 years. All patients were prescribed antiarrhythmic therapy but it proved ineffective. In 15 % of patients, restoration of the sinus rhythm was attempted through electrical cardioversion but long-term control of the sinus rhythm wasn’t achieved. All patients were diagnosed with organic pathology of the mitral valve. Also, in 80 % of patients, relative insufficiency of the tricuspid valve was detected. Chronic heart failure functional class per NYHA was III. Size of the left atrium was 5 cm, mean left ventricular ejection fraction was 61 %. All patients underwent electrical cardioversion. After successful restoration of the sinus rhythm, endocardial electrophysiology study (EES of the heart was performed. Then, correction of valvular pathologies and the Labyrinth IIIB surgery were performed. Results. Examination of refractoriness of different parts of the atriums has shown that effective refractory period (ERP of the atrioventricular node was minimal compared to other parts of the atriums. Maximal ERP duration was observed in the upper part of the right atrium. Therefore, in patients with long history of AF, heterogeneity of atrial myocardium ERP duration is observed. In 17 % of patients, atrial vulnerability was detected. The area of atrial vulnerability was always associated with ERP. Its duration in patients with atrial vulnerability was significantly higher.Conclusion. Long

  4. Pla a 2 and Pla a 3 reactivities identify plane tree-allergic patients with respiratory symptoms or food allergy.

    Science.gov (United States)

    Scala, E; Cecchi, L; Abeni, D; Guerra, E C; Pirrotta, L; Locanto, M; Giani, M; Asero, R

    2017-04-01

    Nine hundred and thirty-nine rPla a 1, nPla a 2, and rPla a 3 ImmunoCAP ISAC reactors were studied. nPla a 2 pos MUXF3 pos but Pla a 1/2 neg subjects were excluded from the study because they were cross-reactive carbohydrate determinant reactors. Among the 764 remaining participants, 71.9% were Pla a 3 pos , 54.1% Pla a 2 pos , and 10.9% Pla a 1 pos . Among Pla a 3 reactors, 89.6% were Pru p 3 pos and 86.8% Jug 3 pos , but the strongest IgE recognition relationship was observed between Pla a 3 and Jug r 3. Distinctive clinical subsets could be documented among plane tree-allergic patients. Pla a 3 reactors had both local and systemic food-induced reactions, but lower past respiratory symptoms occurrence. Pla a 2 reactivity was associated with respiratory symptoms but inversely related to systemic reactions to food. Cosensitization to Pla a 2 and Pla a 3 was associated with a lower past incidence of severe food-induced reactions. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. PLA realizations for VLSI state machines

    Science.gov (United States)

    Gopalakrishnan, S.; Whitaker, S.; Maki, G.; Liu, K.

    1990-01-01

    A major problem associated with state assignment procedures for VLSI controllers is obtaining an assignment that produces minimal or near minimal logic. The key item in Programmable Logic Array (PLA) area minimization is the number of unique product terms required by the design equations. This paper presents a state assignment algorithm for minimizing the number of product terms required to implement a finite state machine using a PLA. Partition algebra with predecessor state information is used to derive a near optimal state assignment. A maximum bound on the number of product terms required can be obtained by inspecting the predecessor state information. The state assignment algorithm presented is much simpler than existing procedures and leads to the same number of product terms or less. An area-efficient PLA structure implemented in a 1.0 micron CMOS process is presented along with a summary of the performance for a controller implemented using this design procedure.

  6. Managing Conflict: Examining Recent PLA Writings on Escalation Control

    Science.gov (United States)

    2016-02-01

    Cleared for Public Release Managing Conflict: Examining Recent PLA Writings on Escalation Control Alison A. Kaufman, Daniel...ANSI Std. Z39.18 i Abstract This study examines how people in China’s People’s Liberation Army ( PLA ) think about and discuss...escalation control in their public writings. It draws on over two dozen PLA writings, most issued since 2008, to explore the current state of PLA

  7. Flax fiber reinforced PLA composites: studies on types of PLA and different methods of fabrication

    CSIR Research Space (South Africa)

    Kumar, R

    2011-05-01

    Full Text Available Natural fibers are used as reinforcement material for number of thermoplastic/thermoset polymers. The interest in using polylactic acid (PLA) as thermoplastic matrix to produce composites completely from 100% renewable resources has increased...

  8. PLA 2010 Conference: Plenty for the Price

    Science.gov (United States)

    Miller, Rebecca

    2010-01-01

    This article outlines Public Library Association (PLA) 2010 annual conference to be held in Oregon Convention Center, Portland on March 23-27. The days quickly fill up with the picks of over 100 programs as well as valuable "talk tables" and special events. The well-organized schedule, divided into eight broad tracks (e.g., technology,…

  9. Influence of dynamic compressive loading on the in vitro degradation behavior of pure PLA and Mg/PLA composite.

    Science.gov (United States)

    Li, Xuan; Qi, Chenxi; Han, Linyuan; Chu, Chenglin; Bai, Jing; Guo, Chao; Xue, Feng; Shen, Baolong; Chu, Paul K

    2017-12-01

    The effects of dynamic compressive loading on the in vitro degradation behavior of pure poly-lactic acid (PLA) and PLA-based composite unidirectionally reinforced with micro-arc oxidized magnesium alloy wires (Mg/PLA) are investigated. Dynamic compressive loading is shown to accelerate degradation of pure PLA and Mg/PLA. As the applied stress is increased from 0.1MPa to 0.9MPa or frequency from 0.5Hz to 2.5Hz, the overall degradation rate goes up. After immersion for 21days at 0.9MPa and 2.5Hz, the bending strength retention of the composite and pure PLA is 60.1% and 50%, respectively. Dynamic loading enhances diffusion of small acidic molecules resulting in significant pH decrease in the immersion solution. The synergistic reaction between magnesium alloy wires and PLA in the composite is further clarified by electrochemical tests. The degradation behavior of the pure PLA and PLA matrix in the composite under dynamic conditions obey the first order degradation kinetics and a numerical model is postulated to elucidate the relationship of the bending strength, stress, frequency, and immersion time under dynamic conditions. We systematically study the influence of dynamic loading on the degradation behavior of pure PLA and Mg/PLA. Dynamic compressive loading is shown to accelerate degradation of pure PLA and Mg/PLA. The synergistic reaction between magnesium alloy wires and PLA in the composite is firstly clarified by electrochemical tests. The degradation behavior of the pure PLA and PLA matrix in the composite under dynamic conditions obey the first order degradation kinetics. Then, a numerical model is postulated to elucidate the relationship of the bending strength, stress, frequency, and immersion time under dynamic conditions. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Common Atrium with Unusual Electrocardiogram in Ellis-van Creveld Syndrome: A Case Report

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2015-01-01

    This report describes a case of common atrium with unusual electrocardiographic findings in a patient with EVC syndrome. This 17-year-old male of Indian origin born of a consanguineous marriage had short stature, genu valgum, polydactyly, gingival hypertrophy, multiple frenula, common atrium, and right axis deviation of QRS with clockwise depolarization in electrocardiogram.

  11. Detection of sequential activation of left atrium and coronary sinus musculature in the general population

    Directory of Open Access Journals (Sweden)

    Masaki Ota, MD

    2016-12-01

    Conclusions: Far-field LA potentials are often recorded in the CS during sequential LA and CSM activation in the general population. The timing of LA potentials in CS recordings reflected the direction of conduction across the CSM.

  12. Prevalence and predictors of low voltage zones in the left atrium in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Huo, Yan; Gaspar, Thomas; Pohl, Matthias

    2017-01-01

    of LVZ. Conclusion: In a large cohort of patients undergoing ablation for AF, the prevalence of LVZ was higher and LVZ areas larger in patients with persistent as compared with paroxysmal AF. The most frequent localization of LVZ was anterior wall, septum and posterior wall. Presence of LVZ...

  13. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging

    Science.gov (United States)

    Poly(lactic acid) (PLA) fibers of submicron sizes encapsulating allyl isothiocyanate (AITC) (PfA) were made and electrospun onto the surfaces of PLA films (PfA-g-film). SEM examination confirmed that the fibers were grafted to the PLA film after the (PfA-g-film) underwent air blowing and water washi...

  14. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    Science.gov (United States)

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films. Published by Elsevier B.V.

  15. The Relationship between Left Atrial Mechanical Function and Functional Capacity in Mitral Stenosis

    Directory of Open Access Journals (Sweden)

    Mücahit Yetim

    2013-11-01

    Full Text Available Aim: In this study, left atrial functions of patients with rheumatic mitral stenosis and sinus rhythm, which was determined by transthorasic echocardiography, was compared with those of healhty subjects and the association of left atrial functions with functional capacity was investigated in subgroup analyses.   Material and methods: 32 patients with isolated rheumatic mitral stenosis (median age was 39.1±11  (group 1 and 20 patients in the control group ( median age was 37±8,2 (group 2 were enrolled to study. The average mitral valve area of patients was 1.1±0,3 cm2. When patients were divided according to New York Heart Association (NYHA classification ; 16 patients were NYHA 2 (Grup A and 16 patients were NYHA 3 (Grup B. There were not any asymptomatic patients and no patients were NYHA 4. Left atrium diameters, left atrium volume, left atrium fractional area change and left atrium ejection fractions  of patients in these groups were calculated.   Results: The demographic characteristics of patients is shown in table 1. Left atrium ejection fraction (LAEF and left atrium fractional area change (LAFAC that were determined echocardiographycally were significantly lower in patients with mitral stenosis (32 ± 5, 44 ± 3; p<0.001- 25 ± 11, 32 ± 6; p< 0.02.  When patients were divided according to New York Heart Association (NYHA classification ; 16 patients were NYHA 2 (Grup A and 16 patients were NYHA 3 (Grup B. There were not any asymptomatic patients and no patients were NYHA 4. The clinical and echocardiographic data of patients are shown in table 2. Despite of similar mitral valve area and average mitral gradient ,systolic pulmonary artery pressure was found to be higher in symptomatic group. But there was no difference between left atrial functions of the two groups.   Discussion: In this study we have shown that left atrial functions determined echocardiographically  can decline in patients with mitral stenosis but the

  16. In vitro degradation kinetics of pure PLA and Mg/PLA composite: Effects of immersion temperature and compression stress.

    Science.gov (United States)

    Li, Xuan; Chu, Chenglin; Wei, Yalin; Qi, Chenxi; Bai, Jing; Guo, Chao; Xue, Feng; Lin, Pinghua; Chu, Paul K

    2017-01-15

    The effects of the immersion temperature and compression stress on the in vitro degradation behavior of pure poly-lactic acid (pure-PLA) and PLA-based composite unidirectionally reinforced with micro-arc oxidized magnesium alloy wires (Mg/PLA or MAO-MAWs/PLA) are investigated. The degradation kinetics of pure-PLA and the PLA matrix in MAO-MAWs/PLA exhibit an Arrhenius-type behavior. For the composite, the synergic degradation of MAO-MAWs maintains a steady pH and mitigates the degradation of PLA matrix during immersion. However, the external compression stress decreases the activation energy (E a ) and pre-exponential factor (k 0 ) consequently increasing the degradation rate of PLA. Under a compression stress of 1MPa, E a and k 0 of pure PLA are 57.54kJ/mol and 9.74×10 7 day -1 , respectively, but 65.5kJ/mol and 9.81×10 8 day -1 for the PLA matrix in the composite. Accelerated tests are conducted in rising immersion temperature in order to shorten the experimental time. Our analysis indicates there are well-defined relationships between the bending strength of the specimens and the PLA molecular weight during immersion, which are independent of the degradation temperature and external compression stress. Finally, a numerical model is established to elucidate the relationship of bending strength, the PLA molecular weight, activation energy, immersion time and temperature. We systematically evaluate the effects of compression stress and temperature on the degradation properties of two materials: (pure-PLA) and MAO-MAWs/PLA (or Mg/PLA). The initial in vitro degradation kinetics of the unstressed or stressed pure-PLA and MAO-MAWs/PLA composite is confirmed to be Arrhenius-like. MAO-MAWs and external compression stress would influence the degradation activation energy (E a ) and pre-exponential factor (k 0 ) of PLA, and we noticed there is a linear relationship between E a and ln k 0 . Thereafter, we noticed that Mg 2+ , not H + , plays a significant role on the

  17. Incisional left atrial isolation for ablation of atrial fibrillation in mitral valve surgery.

    Science.gov (United States)

    Graffigna, Angelo; Branzoli, Stefano; Sinelli, Stefano; Vigano, Mario

    2009-01-01

    The renewed interest in surgical techniques for atrial fibrillation (AF) limited to the left atrium has risen the importance of the original technique of left atrial isolation by means of surgical incision. Transmurality of lesions and cost containment are strong elements to be appreciated in this technique.

  18. Inotropic effects of extracts of Psidium guajava L. (guava) leaves on the guinea pig atrium.

    Science.gov (United States)

    Conde Garcia, E A; Nascimento, V T; Santiago Santos, A B

    2003-05-01

    Many pharmacological effects have been ascribed to extracts of Psidium guajava L. (guava) leaves. However, in spite of its widespread use in Brazilian folk medicine and a reasonable number of scientific reports about it, we could not find any study dealing with its action on the mammalian myocardium. In the present study, by measuring isometric force, we observed that the crude extract of P. guajava (water-alcohol extract obtained by macerating dry leaves) depresses the guinea pig atrial contractility in a concentration-dependent fashion (N = 8 hearts, 15 trials). The compound with cardiac activity was concentrated by extraction in a Soxhlet apparatus using 17 M glacial acetic acid after removing the less polar fractions (hexane, chloroform, acetone, ethanol and methanol), suggesting that this compound is a highly polar substance. In the isolated guinea pig left atrium the acetic acid fraction (10-800 mg/l) of P. guajava 1) reversibly decreased myocardial force in a concentration-dependent fashion (EC50 = 0.07g/l, N = 5 hearts, 9 trials, Pleaves depress myocardial inotropism.

  19. Echocardiographic study of left atrial myxoma

    Directory of Open Access Journals (Sweden)

    Dalal J

    1979-01-01

    Full Text Available Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardio-graphic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the my-xomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete dis-appearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.

  20. Study on simulation methods of atrium building cooling load in hot and humid regions

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yiqun; Li, Yuming; Huang, Zhizhong [Institute of Building Performance and Technology, Sino-German College of Applied Sciences, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Wu, Gang [Weldtech Technology (Shanghai) Co. Ltd. (China)

    2010-10-15

    In recent years, highly glazed atria are popular because of their architectural aesthetics and advantage of introducing daylight into inside. However, cooling load estimation of such atrium buildings is difficult due to complex thermal phenomena that occur in the atrium space. The study aims to find out a simplified method of estimating cooling loads through simulations for various types of atria in hot and humid regions. Atrium buildings are divided into different types. For every type of atrium buildings, both CFD and energy models are developed. A standard method versus the simplified one is proposed to simulate cooling load of atria in EnergyPlus based on different room air temperature patterns as a result from CFD simulation. It incorporates CFD results as input into non-dimensional height room air models in EnergyPlus, and the simulation results are defined as a baseline model in order to compare with the results from the simplified method for every category of atrium buildings. In order to further validate the simplified method an actual atrium office building is tested on site in a typical summer day and measured results are compared with simulation results using the simplified methods. Finally, appropriate methods of simulating different types of atrium buildings are proposed. (author)

  1. Non-isothermal crystallization of PET/PLA blends

    International Nuclear Information System (INIS)

    Chen, Huipeng; Pyda, Marek; Cebe, Peggy

    2009-01-01

    Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry and X-ray scattering. The PET/PLA blends, prepared by solution casting, were found to be miscible in the melt over the entire composition range. Both quenched amorphous and semicrystalline blends exhibit a single, composition dependent glass transition temperature. We report the non-isothermal crystallization of (a) PET, with and without the presence of PLA crystals and (b) PLA, with and without the presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and degree of crystallinity of PET decreases as PLA content increases. In contrast, PLA crystallization is strongly affected by the mobility of the PET fraction. When PET is wholly amorphous, PLA can crystallize even in 70/30 blends, albeit weakly. But when PET is crystalline, PLA cannot crystallize when its own content drops below 0.90. These different behaviors may possibly be related to the tendency of each polymer to form constrained chains, i.e., to form the rigid amorphous fraction, or RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, the rigid amorphous fraction of one polymer component may inhibit the growth of crystals of the other blend partner.

  2. Operational experience for the latest generation of ATRIUM trademark 10 fuel assemblies

    International Nuclear Information System (INIS)

    Schoss, Volker; Hoffmann, Petra Britt; Schaefer, Jens

    2011-01-01

    AREVA NP's ATRIUM trademark 10 product family was first introduced to the BWR market in 1992. Lead test campaigns confirmed the outstanding product performance and justified introduction of reload quantities. Further development of particular product features was demonstrated and implemented in the fuel design to meet highest expectations for reliability and fuel economics. The latest generation called ATRIUM trademark 10XP and subsequently ATRIUM trademark 10XM was introduced in 2002 and 2005, respectively. The first lead test assemblies completed their operation successfully after seven cycles. (orig.)

  3. Development of polylactide (PLA) and PLA nanocomposite foams in injection molding for automotive applications

    Science.gov (United States)

    Najafi Chaloupli, Naqi

    Plastic materials are extensively used in automotive structures since they make cars more energy efficient. Recently, the automotive industry is searching for bio-based and renewable alternatives to petroleum-based plastics to reduce the dependence on fossil fuels. Among polymers originating from renewable sources, polylactide (PLA) has attracted significant interest. The use of this polymer in durable industries is promising. Fuel-efficient automobiles are nowadays demanded due to the increasing concerns about environmental and fuel issues. The automobile fuel efficiency can be improved by using a lightweight material and, thereby, reducing the automobile weight. A potential method to achieve this objective is the use of the foaming technology. Foam is a material where a gas phase is encapsulated by a solid phase. Foaming technology helps to manufacture lightweight parts with superior properties in comparison with their solid counterparts. The basic mechanisms of foaming process normally consists of gas implementation, formation of uniform polymer-gas solution, cell nucleation, cell growth and, finally, cell stabilization. PLA foaming has, however, proved to be difficult mainly due to poor rheological properties, small processing window, and slow crystallization kinetics. The ultimate purpose of this work is to reduce by 30 % the weight of polylactide (PLA)-clay based nanocomposites by manufacturing injection-molded foamed parts. To use standard processing equipment, a chemical blowing agent (CBA) was employed. The injection molding technique was utilized in this project because it is the most widely used fabrication process in industry that can produce complex shaped articles. This process, however, is more challenging than other foaming processes since it deals with many additional controlling parameters. In the first part of this project, we illustrated how long chain branching (LCB) and molecular structure impact the melt rheology, crystallization and batch

  4. PLA/chitosan/keratin composites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tanase, Constantin Edi, E-mail: etanase@live.com [Faculty of Medical Bioengineering, ‘Grigore T. Popa’ University of Medicine and Pharmacy, 9-13 Kogalniceanu Street, 700454 Iasi (Romania); Spiridon, Iuliana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2014-07-01

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior.

  5. PLA/chitosan/keratin composites for biomedical applications

    International Nuclear Information System (INIS)

    Tanase, Constantin Edi; Spiridon, Iuliana

    2014-01-01

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior

  6. Nanocellulose fibers applied in PLA composites for food packaging applications

    DEFF Research Database (Denmark)

    Trifol Guzman, Jon; Garciad, A.; Mericer, C.

    Poly (lactic acid) (PLA) has long been advocated as one of the best candidates for bio-based food packaging, but low thermal stability, slow crystallization, high oxygen and water permeability are drawbacks that still limits the use of PLA in a broader range of applications.The goal...... of this research project has been to improve the permeability of PLA by use of nanocellulose or by combination of nanocellulose and nanoclay in PLA composites. The cellulose nanofibers (CNF) were extracted from sisal fibers using an optimized up-scalable three-step chemical protocol. Composites with both CNF...... properties of PLA. In particular 1 wt% of CNF and NC resulted in a 63% of reduction on the oxygen transmission rate and a 57% on the water vapor transmission rate, while a 5 wt% PLA/CNF/NC resulted in a 89% and a 75% of decrease respectively....

  7. Extreme premature with persistent left superior vena cava.

    Science.gov (United States)

    Aboitiz-Rivera, Carlos Manuel; Blachman-Braun, Ruben; Parra-Pérez, Mariana Yazmin

    2017-10-01

    Persistent left superior vena cava (PLSVC) is a congenital anomaly, that results when there is an absence of the normal regression of the left common precardinal vein during embryogenesis. Usually, this anomaly remains asymptomatic, however, when the PLSVC drains into the left atrium this could lead to a right-to-left shunt. Additionally, this can result in inadvertent delivery of air or thrombus into the systemic circulation with potential neurologic, cardiac and renal complications. In this article, we present a case of an extreme premature Mexican newborn in which the diagnosis was made after placement of a percutaneous central venues catheter.

  8. Chinas Goldwater-Nichols Assessing PLA Organizational Reforms

    Science.gov (United States)

    2016-04-01

    Liberation Army ( PLA ): the Central Military Commission (CMC) has been revamped, the four general departments dissolved, new service headquarters... PLA insti- tutions, force structure, and policy that will be ongoing through 2020. In pursuing these reforms, China’s leaders hope both to tighten...central politi- cal control over a force that was seen as increasingly corrupt and to build the PLA into a credible joint warfighting entity. Yet

  9. Chinese Cyber Espionage: A Complementary Method to Aid PLA Modernization

    Science.gov (United States)

    2015-12-01

    COMPLEMENTARY METHOD TO AID PLA MODERNIZATION by Jamie M. Ellis December 2015 Thesis Advisor: Wade L. Huntley Second Reader: Christopher R. Twomey THIS...Master’s Thesis 4. TITLE AND SUBTITLE CHINESE CYBER ESPIONAGE: A COMPLEMENTARY METHOD TO AID PLA MODERNIZATION 5. FUNDING NUMBERS 6. AUTHOR(S) Jamie M...DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) In 2013, Mandiant published a report linking one People’s Liberation Army ( PLA ) unit to the

  10. Augmentation of a Microbial Consortium for Enhanced Polylactide (PLA) Degradation.

    Science.gov (United States)

    Nair, Nimisha R; Sekhar, Vini C; Nampoothiri, K Madhavan

    2016-03-01

    Bioplastics are eco-friendly and derived from renewable biomass sources. Innovation in recycling methods will tackle some of the critical issues facing the acceptance of bioplastics. Polylactic acid (PLA) is the commonly used and well-studied bioplastic that is presumed to be biodegradable. Considering their demand and use in near future, exploration for microbes capable of bioplastic degradation has high potential. Four PLA degrading strains were isolated and identified as Penicillium chrysogenum, Cladosporium sphaerospermum, Serratia marcescens and Rhodotorula mucilaginosa. A consortium of above strains degraded 44 % (w/w) PLA in 30 days time in laboratory conditions. Subsequently, the microbial consortium employed effectively for PLA composting.

  11. Creating marketing strategies for wedding business unit of Amari Atrium Hotel

    OpenAIRE

    Suvagondha, Apiwat; Soparat, Pattamaporn

    2008-01-01

    Abstract Date: May 29, 2008 Course: Master Thesis (EFO 705) Authors: Apiwat Suvagondha 790819 Pattamaporn Soparat 840216 Tutor: Tobias Eltebrandt Title: Creating marketing strategies for wedding business unit of Amari Atrium Hotel Problem: What should be marketing strategies for wedding business unit of Amari Atrium Hotel? Purpose: The aim of our thesis is to analyze the wedding market in Bangkok together with consumer purchasing behavior of Thai’s couple regarding to wedding ceremony in orde...

  12. Atorvastatin can ameliorate left atrial stunning induced by radiofrequency ablation for atrial fibrillation.

    Science.gov (United States)

    Xie, Ruiqin; Yang, Yingtao; Cui, Wei; Yin, Hongning; Zheng, Hongmei; Zhang, Jidong; You, Ling

    2017-09-01

    The objective of this study was to study the functional changes of the left atrium after radiofrequency ablation treatment for atrial fibrillation and the therapeutic effect of atorvastatin. Fifty-eight patients undergoing radiofrequency ablation for atrial fibrillation were randomly divided into non-atorvastatin group and atorvastatin group. Patients in the atorvastatin group were treated with atorvastatin 20 mg p.o. per night in addition to the conventional treatment of atrial fibrillation; patients in the non-atorvastatin group received conventional treatment of atrial fibrillation only. Echocardiography was performed before radiofrequency ablation operation and 1 week, 2 weeks, 3 weeks, and 4 weeks after operation. Two-dimensional ultrasound speckle tracking imaging system was used to measure the structural indexes of the left atrium. Results indicated that there was no significant change for indexes representing the structural status of the left atrium within a month after radiofrequency ablation (P > 0.05); however, there were significant changes for indexes representing the functional status of the left atrium. There were also significant changes in indexes reflecting left atrial strain status: the S and SRs of atorvastatin group were higher than those of non-atorvastatin group (P atorvastatin could improve left atrial function and shorten the duration of atrial stunning after radiofrequency ablation of atrial fibrillation.

  13. Malignant inferior vena cava obstruction involving right atrium. Palliative treatment with self expandable metallic stent

    International Nuclear Information System (INIS)

    Shao Guoliang; Wang Jianhua; Zhou Kangrong; Yan Zhiping

    2001-01-01

    Objective: To investigate the safety and efficacy of placement of self-expandable metallic stent within right atrium and inferior vena cava (ICV) in patients with malignant ICV obstruction involving right atrium. Methods: There were 5 male patients with advanced hepatocellular carcinoma, aged from 42 to 65 years (mean 56.3 years). The malignancies invaded right atrium and ICV simultaneously, and caused obstruction of ICV. These patients presented symptoms and signs of obstruction of ICV such as hepatomegaly, ascites, edema of lower extremities. 'Z' type stainless steel stents (7.5-10.0 cm in length and 2.5 cm in diameter) were selected for these patients. Part (1.0-3.0 cm in length) of stent was placed in right atrium and the rest was in ICV. Results: All of stents were placed successfully and obstructed ICV reopened. The symptoms of obstruction of ICV relieved or disappeared. There were no recurrence of symptoms of obstruction of ICV and any cardiac complication related to placement of stents in follow-up period (67-188 days). Conclusion: Placement of self-expandable metallic stent within right atrium and ICV in treatment of patients with malignant ICV obstruction involving right atrium is one of the safe and effective methods

  14. PLA Reforms and Chinas Nuclear Forces

    Science.gov (United States)

    2016-10-01

    Specifically, “the value and the capability of the Rocket Force should lie in the strengthening of the credible and reliable nuclear deterrence and... deterrent imply a cap on the size of nuclear forces and the missions as- signed to them.41 However, the Rocket Force could seek to capitalize on its...JFQ 83, 4th Quarter 2016 Logan 57 PLA Reforms and China’s Nuclear Forces By David C. Logan C hina is in the midst of sweeping military reforms that

  15. Exploring the in vitro and in vivo compatibility of PLA, PLA/GNP and PLA/CNT-COOH biodegradable nanocomposites: Prospects for tendon and ligament applications.

    Science.gov (United States)

    Correia Pinto, Viviana; Costa-Almeida, Raquel; Rodrigues, Ilda; Guardão, Luísa; Soares, Raquel; Miranda Guedes, Rui

    2017-08-01

    Anterior cruciate ligament (ACL) reconstructive surgeries are the most frequent orthopedic procedures in the knee. Currently, existing strategies fail in completely restoring tissue functionality and have a high failure rate associated, presenting a compelling argument towards the development of novel materials envisioning ACL reinforcement. Tendons and ligaments, in general, have a strong demand in terms of biomechanical features of developed constructs. We have previously developed polylactic acid (PLA)-based biodegradable films reinforced either with graphene nanoplatelets (PLA/GNP) or with carboxyl-functionalized carbon nanotubes (PLA/CNT-COOH). In the present study, we comparatively assessed the biological performance of PLA, PLA/GNP, and PLA/CNT-COOH by seeding human dermal fibroblasts (HFF-1) and studying cell viability and proliferation. In vivo tests were also performed by subcutaneous implantation in 6-week-old C57Bl/6 mice. Results showed that all formulations studied herein did not elicit cytotoxic responses in seeded HFF-1, supporting cell proliferation up to 3 days in culture. Moreover, animal studies indicated no physiological signs of severe inflammatory response after 1 and 2 weeks after implantation. Taken together, our results present a preliminary assessment on the compatibility of PLA reinforced with GNP and CNT-COOH nanofillers, highlighting the potential use of these carbon-based nanofillers for the fabrication of reinforced synthetic polymer-based structures for ACL reinforcement. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2182-2190, 2017. © 2017 Wiley Periodicals, Inc.

  16. The Prognostic Value of Left Atrial Peak Reservoir Strain in Acute Myocardial Infarction Is Dependent on Left Ventricular Longitudinal Function and Left Atrial Size

    DEFF Research Database (Denmark)

    Ersbøll, Mads; Andersen, Mads J; Valeur, Nana

    2013-01-01

    of PALS and left ventricular longitudinal strain (global longitudinal strain) in large-scale populations in regard to prognosis. METHODS AND RESULTS: We prospectively included 843 patients (mean age 62.1+/-11.8; 74% male) with acute myocardial infarction and measured global longitudinal strain, left......BACKGROUND: Peak atrial longitudinal strain (PALS) during the reservoir phase has been proposed as a measure of left atrium function in a range of cardiac conditions, with the potential for added pathophysiological insight and prognostic value. However, no studies have assessed the interrelation...

  17. Left atrial volume and function in patients following ST elevation myocardial infarction and the association with clinical outcome

    DEFF Research Database (Denmark)

    Lønborg, Jacob Thomsen; Engstrøm, Thomas; Møller, Jacob Eifer

    2013-01-01

    The left atrium (LA) transfers blood to the left ventricle in a complex manner. LA function is characterized by passive emptying (LA passive fraction), active emptying (LA ejection fraction), and total emptying (LA fractional change). Despite this complexity, the clinical relevance of the LA is b...... function in patients following ST elevation myocardial infarction (STEMI)....

  18. Left ventricular outflow tract to left atrial communication secondary to rupture of mitral-aortic intervalvular fibrosa in infective endocarditis: diagnosis by transesophageal echocardiography and color flow imaging.

    Science.gov (United States)

    Bansal, R C; Graham, B M; Jutzy, K R; Shakudo, M; Shah, P M

    1990-02-01

    Infection of the mitral-aortic intervalvular fibrosa occurs most commonly in association with infective endocarditis of the aortic valve. Infection of the aortic valve results in a regurgitant jet that presumably strikes this subaortic interannular zone of fibrous tissue and produces a secondary site of infection. Infection of this interannular zone then leads to the formation of subaortic abscess or pseudoaneurysm of the left ventricular outflow tract. This infected zone of mitral-aortic intervalvular fibrosa or subaortic aneurysm can subsequently rupture into the left atrium with systolic ejection of blood from the left ventricular outflow tract to the left atrium. This report describes the echocardiographic findings in three patients with pathologically proved left ventricular outflow tract to left atrial communication. Precise preoperative diagnosis is important, and this lesion should be differentiated from ruptured aneurysm of the sinus of Valsalva and perforation of the anterior mitral leaflet. Transthoracic echocardiography using color flow imaging and conventional Doppler techniques may show an eccentric mitral regurgitation type of signal in the left atrium originating from the region of the left ventricular outflow tract. However, transesophageal echocardiography provides an accurate preoperative diagnosis and should be used intraoperatively during repair of such lesions.

  19. Polylactic acid (PLA) controlled delivery carriers for biomedical applications.

    Science.gov (United States)

    Tyler, Betty; Gullotti, David; Mangraviti, Antonella; Utsuki, Tadanobu; Brem, Henry

    2016-12-15

    Polylactic acid (PLA) and its copolymers have a long history of safety in humans and an extensive range of applications. PLA is biocompatible, biodegradable by hydrolysis and enzymatic activity, has a large range of mechanical and physical properties that can be engineered appropriately to suit multiple applications, and has low immunogenicity. Formulations containing PLA have also been Food and Drug Administration (FDA)-approved for multiple applications making PLA suitable for expedited clinical translatability. These biomaterials can be fashioned into sutures, scaffolds, cell carriers, drug delivery systems, and a myriad of fabrications. PLA has been the focus of a multitude of preclinical and clinical testing. Three-dimensional printing has expanded the possibilities of biomedical engineering and has enabled the fabrication of a myriad of platforms for an extensive variety of applications. PLA has been widely used as temporary extracellular matrices in tissue engineering. At the other end of the spectrum, PLA's application as drug-loaded nanoparticle drug carriers, such as liposomes, polymeric nanoparticles, dendrimers, and micelles, can encapsulate otherwise toxic hydrophobic anti-tumor drugs and evade systemic toxicities. The clinical translation of these technologies from preclinical experimental settings is an ever-evolving field with incremental advancements. In this review, some of the biomedical applications of PLA and its copolymers are highlighted and briefly summarized. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. PLA-Based Curriculum: Humanistic Model of Higher Education

    Science.gov (United States)

    Popova-Gonci, Viktoria; Tobol, Amy Ruth

    2011-01-01

    The authors believe that there is no inherent academic validity or lack of thereof in the notion of prior learning assessment (PLA)-based curriculum. If mishandled, it can become the tool for carrying out diploma mill practices. Conversely, if implemented and facilitated appropriately, PLA-based curricula can offer humanistic educational values…

  1. The internalization of fluorescence-labeled PLA nanoparticles by macrophages.

    Science.gov (United States)

    Li, Fengjuan; Zhu, Aiping; Song, Xiaoli; Ji, Lijun; Wang, Juan

    2013-09-10

    Rhodamine B (RhB)-labeled PLA nanoparticles were prepared through surface grafting copolymerization of glycidyl methacrylate (GMA) onto PLA nanoparticles during the emulsion/evaporation process. RhB firstly interacts with sodium dodecyl sulfate (SDS) through electrostatic interaction to form hydrophobic complex (SDS-RhB). Due to the high-affinity of SDS-RhB with GMA, hydrophilic RhB can be successfully combined into PLA nanoparticles. The internalization of RhB-labeled PLA nanoparticles by macrophages was investigated with fluorescence microscope technology. The effects of the PLA nanoparticle surface nature and size on the internalization were investigated. The results indicate that the PLA particles smaller than 200 nm can avoid the uptake of phagocytosis. The bigger PLA particles (300 nm) with polyethylene glycol (PEG) surface showed less internalization by macrophage compared with those with poly(ethylene oxide-propylene oxide) copolymer (F127) or poly(vinyl alcohol) (PVA) surface. The "stealth" function of PEG on the PLA nanoparticles from internalization of macrophages due to the low protein adsorption is revealed by electrochemical impedance technology. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. PLA Binaries in the Context of Competency-Based Assessment

    Science.gov (United States)

    Popova, Viktoria; Clougherty, R. J., Jr.

    2014-01-01

    In this article, the authors report that, as the importance of competency-based learning (CBL) in higher education discourse surges, it not only further validates prior learning assessment (PLA), but it demonstrates PLA's essential nature as an important framework for assessing learning that has been acquired outside of traditional academia.…

  3. Inotropic effects of extracts of Psidium guajava L. (guava leaves on the guinea pig atrium

    Directory of Open Access Journals (Sweden)

    Conde Garcia E.A.

    2003-01-01

    Full Text Available Many pharmacological effects have been ascribed to extracts of Psidium guajava L. (guava leaves. However, in spite of its widespread use in Brazilian folk medicine and a reasonable number of scientific reports about it, we could not find any study dealing with its action on the mammalian myocardium. In the present study, by measuring isometric force, we observed that the crude extract of P. guajava (water-alcohol extract obtained by macerating dry leaves depresses the guinea pig atrial contractility in a concentration-dependent fashion (N = 8 hearts, 15 trials. The compound with cardiac activity was concentrated by extraction in a Soxhlet apparatus using 17 M glacial acetic acid after removing the less polar fractions (hexane, chloroform, acetone, ethanol and methanol, suggesting that this compound is a highly polar substance. In the isolated guinea pig left atrium the acetic acid fraction (10-800 mg/l of P. guajava 1 reversibly decreased myocardial force in a concentration-dependent fashion (EC50 = 0.07g/l, N = 5 hearts, 9 trials, P<0.05, 2 increased the atrial relaxation time measured at 20% of the force amplitude up to 35% (91 ± 15 to 123 ± 30 ms, N = 3 hearts, 6 trials, P<0.05, 3 abolished the positive staircase effect (Bowditch phenomenon in a concentration-dependent fashion suggesting a decrease of the cellular inward calcium current (N = 4 hearts, 8 trials, P<0.05, and 4 its inotropic effect was abolished by cholinergic receptor blockade with 1.5 mM atropine sulfate, indicating a cholinergic involvement in the mechanism of action of the extract (N = 7 hearts, 15 trials, P<0.05. The acetic acid extract was 20 times more potent than crude extract (EC50 = 1.4 g/l. The results showed that extracts from P. guajava leaves depress myocardial inotropism.

  4. An overview of the recent developments in polylactide (PLA) research.

    Science.gov (United States)

    Madhavan Nampoothiri, K; Nair, Nimisha Rajendran; John, Rojan Pappy

    2010-11-01

    The concept of biodegradable plastics is of considerable interest with respect to solid waste accumulation. Greater efforts have been made in developing degradable biological materials without any environmental pollution to replace oil-based traditional plastics. Among numerous kinds of degradable polymers, polylactic acid sometimes called polylactide, an aliphatic polyester and biocompatible thermoplastic, is currently a most promising and popular material with the brightest development prospect and was considered as the 'green' eco friendly material. Biodegradable plastics like polyglycolic acid, polylactic acid, polycaprolactone, polyhydroxybutyrate, etc. are commercially available for controlled drug releases, implantable composites, bone fixation parts, packaging and paper coatings, sustained release systems for pesticides and fertilizers and compost bags etc. This review will provide information on current PLA market, brief account on recent developments in the synthesis of lactic acid (monomer of PLA) through biological route, PLA synthesis, unique material properties of PLA and modification of those by making copolymers and composites, PLA degradation and its wide spectrum applications.

  5. Anomlus pulmonary venous return aaccompanied by normal superior pulmonary veins in the left upper lobe: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Eon; Kang, Min Jin; Lee, Ji Hae; Bae, Kyung Eun; Kim, Jae Hyung; Kang, Tae Kyung; Kim, Soung Hee; Kim, Ji Young; Jeong, Myeong Ja; Kim, Soo Hyun [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2017-08-15

    Partial anomalous pulmonary venous return is a rare congenital pulmonary venous anomaly, in which some of the pulmonary veins drain into the systemic circulation rather than the left atrium. Many variants of partial anomalous pulmonary venous return have been reported. We present a rare type of partial anomalous pulmonary venous return in which the anomalous left upper lobe pulmonary vein drained into the left innominate vein via the vertical vein, accompanying the left upper lobe pulmonary vein in the normal location.

  6. Anomlus pulmonary venous return aaccompanied by normal superior pulmonary veins in the left upper lobe: A case report

    International Nuclear Information System (INIS)

    Kim, Dong Eon; Kang, Min Jin; Lee, Ji Hae; Bae, Kyung Eun; Kim, Jae Hyung; Kang, Tae Kyung; Kim, Soung Hee; Kim, Ji Young; Jeong, Myeong Ja; Kim, Soo Hyun

    2017-01-01

    Partial anomalous pulmonary venous return is a rare congenital pulmonary venous anomaly, in which some of the pulmonary veins drain into the systemic circulation rather than the left atrium. Many variants of partial anomalous pulmonary venous return have been reported. We present a rare type of partial anomalous pulmonary venous return in which the anomalous left upper lobe pulmonary vein drained into the left innominate vein via the vertical vein, accompanying the left upper lobe pulmonary vein in the normal location

  7. Effects of Potassium Channel Blockers on the Negative Inotropic Responses Induced by Cromakalim and Pinacidil in Guinea Pig Atrium

    Science.gov (United States)

    1992-01-01

    RD-A2•4 875 EFFECTS OF POTASSIUM CHANNEL BLOCKERS ON THE NEGATIVE 1/1 INOTROPIC RESPONSES INDUCED BY CRONAKALIM RND PINACIDIL IN GUINEA PIG ATRIUM(U...INOTROPICTRSPONSES INDUCED BY CROMAKAUM AND PINACIDILIN GUINEA PIG ATRIUM a AUTHOR WAI-MAN LAU 7 FORMING ORG NAMES/ADDRESSES DEFENCE SCIENCE AND a...and Technology Organisaio Aot Val. Negative Inotropic Responses Victoria. Australia Induced by Cromakalim and Pinacidil in Guinea Pig Atrium Key

  8. Drug-conjugated PLA-PEG-PLA copolymers: a novel approach for controlled delivery of hydrophilic drugs by micelle formation.

    Science.gov (United States)

    Danafar, H; Rostamizadeh, K; Davaran, S; Hamidi, M

    2017-12-01

    A conjugate of the antihypertensive drug, lisinopril, with triblock poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA) copolymer was synthesized by the reaction of PLA-PEG-PLA copolymer with lisinopril in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine. The conjugated copolymer was characterized in vitro by hydrogen nuclear magnetic resonance (HNMR), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) techniques. Then, the lisinopril conjugated PLA-PEG-PLA were self-assembled into micelles in aqueous solution. The resulting micelles were characterized further by various techniques such as dynamic light scattering (DLS) and atomic force microscopy (AFM). The results revealed that the micelles formed by the lisinopril-conjugated PLA-PEG-PLA have spherical structure with the average size of 162 nm. The release behavior of conjugated copolymer, micelles and micelles physically loaded by lisinopril were compared in different media. In vitro release study showed that in contrast to physically loaded micelles, the release rate of micelles consisted of the conjugated copolymer was dependent on pH of media where it was higher at lower pH compared to the neutral medium. Another feature of the conjugated micelles was their more sustained release profile compared to the lisinopril-conjugated copolymer and physically loaded micelles.

  9. Study of Effects on Mechanical Properties of PLA Filament which is blended with Recycled PLA Materials

    Science.gov (United States)

    Babagowda; Kadadevara Math, R. S.; Goutham, R.; Srinivas Prasad, K. R.

    2018-02-01

    Fused deposition modeling is a rapidly growing additive manufacturing technology due to its ability to build functional parts having complex geometry. The mechanical properties of the build part is depends on several process parameters and build material of the printed specimen. The aim of this study is to characterize and optimize the parameters such as layer thickness and PLA build material which is mixed with recycled PLA material. Tensile and flexural or bending test are carried out to determine the mechanical response characteristics of the printed specimen. Taguchi method is used for number of experiments and Taguchi S/N ratio is used to identify the set of parameters which give good results for respective response characteristics, effectiveness of each parameters is investigated by using analysis of variance (ANOVA).

  10. All optical programmable logic array (PLA)

    Science.gov (United States)

    Hiluf, Dawit

    2018-03-01

    A programmable logic array (PLA) is an integrated circuit (IC) logic device that can be reconfigured to implement various kinds of combinational logic circuits. The device has a number of AND and OR gates which are linked together to give output or further combined with more gates or logic circuits. This work presents the realization of PLAs via the physics of a three level system interacting with light. A programmable logic array is designed such that a number of different logical functions can be combined as a sum-of-product or product-of-sum form. We present an all optical PLAs with the aid of laser light and observables of quantum systems, where encoded information can be considered as memory chip. The dynamics of the physical system is investigated using Lie algebra approach.

  11. Left atrial leiomyosarcoma as cause of heart failure

    International Nuclear Information System (INIS)

    Valdes Martin, Alexander

    2012-01-01

    The case of a 26 year-old patient with diagnosis of heart failure and presence of a mobile echogenic mass without calcification attached to the posterolateral area of the left atrium was reported. She underwent surgery and tissue examination evidenced a high-grade heart leiomyosarcoma. Postoperative course was satisfactory and her clinical state was rigorously monitored by oncology and heart specialists in the institution

  12. Cine MR imaging in mitral valve prolapse; Study on mitral regurgitation and left atrial volume

    Energy Technology Data Exchange (ETDEWEB)

    Kumai, Toshihiko [Chiba Univ. (Japan). School of Medicine

    1993-02-01

    This study was undertaken to assess the ability of cine MR imaging to evaluate the direction, timing, and severity of mitral regurgitation in patients with mitral valve prolapse (MVP). The population of this study was 33 patients with MVP diagnosed by two-dimensional echocardiography and 10 patients with rheumatic mitral valve disease (MSR) for comparison. 7 patients with MVP and 5 with MSR had atrial fibrillation and/or history of congestive heart failure as complications. Mitral regurgitation was graded for severity by color Doppler flow imaging in all patients. Direction and size of systolic flow void in the left atrium were analyzed by contiguous multilevel cine MR images and the maximum volumes of flow void and left atrium were measured. Although flow void was found at the center of the left atrium in most of MSR, it was often directed along the postero-caudal atrial wall in anterior leaflet prolapse and along the anterocranial atrial wall in posterior leaflet prolapse. In MVP, the maximum volume of flow void was often seen in late systole. The maximum volume of flow void and that of left atrium were significantly larger in patients with atrial fibrillation and/or history of congestive heart failure. The length and volume of flow void were increased with clinical severity and degree of regurgitation determined by color Doppler flow imaging. Thus cine MR imaging provides a useful means for detection and semiquantitative evaluation of mitral regurgitation in subjects with MVP. (author).

  13. “Anomalous right pulmonary artery left atrial fistula”: Growth in vain

    Directory of Open Access Journals (Sweden)

    Vishal Kumar Jain

    2015-12-01

    Full Text Available We report a case of direct communication between the right pulmonary artery and the left atrium; a rare cause of central cyanosis in 10 year old boy, emphasizing the role of multislice computed tomography scanner in delineating the complex vascular abnormality over more invasive conventional angiography.

  14. Nuclear thyroid hormone receptors in rabbit heart: reduced triiodothyronine binding in atrium compared with ventricle

    International Nuclear Information System (INIS)

    Banerjee, S.K.; Ulrich, J.M.; Kaldor, G.J.

    1988-01-01

    Radiolabeled triiodothyronine (T3) binding to isolated nuclei was measured to compare the binding characteristics of the nuclear receptors in rabbit ventricular and atrial muscle cells. Scatchard analysis of the binding data yielded a maximum binding capacity of 170 +/- 20 fmol per mg DNA and apparent dissociation constant of 525 +/- 100 pM for ventricular nuclei. The binding capacity and the dissociation constant for the atrial muscle cell nuclei were 55 +/- 10 fmol per mg DNA and 500 +/- 75 pM, respectively. The results suggest that the binding capacity for T3 receptor in the atrium is considerably lower than that found in the ventricle. The reduced binding capacity of the T3 receptor in the atrium might reflect differences in the nuclear T3 receptors between ventricle and atrium

  15. The Linguistic and Cultural Interpretation of Dissonant Heritage: the ATRIUM Cultural Route

    Directory of Open Access Journals (Sweden)

    Sandra Nauert

    2017-06-01

    Full Text Available The European Cultural Route ATRIUM (Architecture of Totalitarian Regimes in Europe's Urban Memory deals with dissonant heritage, referring to a contrast of meaning and value systems between the past and the present. The route will be examined within the framework of a set of communication strategies for cultural routes. This short paper will look at some linguistic aspects related to the ATRIUM route and its ‘dissonant heritage’. By analysing some examples of existing promotional approaches related to this particular heritage, it will outline some considerations for a communicative strategy appropriate to the overall narrative structure of the ATRIUM cultural route, with special regard to a bottom-up constructivist approach.

  16. Daylighting and Cooling of Atrium Buildings in Warm Climates: Impact of the Top-Fenestration and Wall Mass Area.

    Science.gov (United States)

    Atif, Morad Rachid

    1992-01-01

    Sun-lighting and daylighting contribute greatly to the aesthetic value of an atrium. However, today's atria are often found either over-lit with extensive cooling loads, or under-lit requiring increased artificial lighting loads. The increase of the top-glazing area increases the cooling loads and decreases the lighting loads. The increase of the mass in the atrium walls decreases the maximum atrium temperature and the cooling loads. Furthermore, the mass distribution and its reflectance affect the lighting levels at the atrium floor. The purpose of this study is to investigate the simultaneous impact of the top-fenestration and the mass and reflectance of atrium walls on the cooling and daylighting performance of atria in warm climates. It attempts to determine the optimum top-fenestration for efficient daylighting and low cooling loads. The daylighting performance was evaluated through illumination measurements in physical models in a sky simulator. The cooling performance was evaluated using the software TRNSYS 13.1. Two types of top-fenestration were tested: horizontal and vertical south-facing, each with three alternate areas. The variations of the atrium walls included materials (standard frame and heavyweight concrete) and percentage and reflectance of the solid area. Two and four-story atria were considered, each with square and linear configuration. The performance was evaluated for three warm climates. The optimum top-fenestration for efficient daylighting was determined. The daylighting prediction algorithm was extended to include the effective reflectance of the atrium walls. The increase of mass in the atrium walls significantly decreased the atrium temperature range, the maximum atrium temperature, and the cooling loads. This impact decreased from horizontal to vertical south-facing top-glazing. The vertical south-facing top-glazing and, to a lesser degree, the reduction of the glazed atrium cover by 50% had more cooling benefits than increasing the

  17. Preparation of Chitin-PLA laminated composite for implantable application

    Directory of Open Access Journals (Sweden)

    Romana Nasrin

    2017-12-01

    Full Text Available The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1–20% of PLA reinforced PLA films (CTP were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP were prepared by laminating PLA film (obtained by hot press method with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2 and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa and CTP2 film (8.83 MPa. After lamination of pure PLA and CTP2 film, the composite (LCTP yielded 0.265–1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical

  18. Fabrication of PLA Filaments and its Printable Performance

    Science.gov (United States)

    Liu, Wenjie; Zhou, Jianping; Ma, Yuming; Wang, Jie; Xu, Jie

    2017-12-01

    Fused deposition modeling (FDM) is a typical 3D printing technology and preparation of qualified filaments is the basis. In order to prepare polylactic acid (PLA) filaments suitable for personalized FDM 3D printing, this article investigated the effect of factors such as extrusion temperature and screw speed on the diameter, surface roughness and ultimate tensile stress of the obtained PLA filaments. The optimal process parameters for fabrication of qualified filaments were determined. Further, the printable performance of the obtained PLA filaments for 3D objects was preliminarily explored.

  19. Characterization of PLA parts made with AM process

    Science.gov (United States)

    Spina, Roberto; Cavalcante, Bruno; Lavecchia, Fulvio

    2018-05-01

    The main objective of the presented work is to evaluate the thermal behavior of Poly-lactic acid (PLA) parts made with a Fused Deposition Modelling (FDM) process. By using a robust framework for the testing sequence of PLA parts, with the aim of establishing a standard testing cycle for the optimization of the part performance and quality. The research involves study the materials before and after 3D printing. Two biodegradable PLA polymers are investigated, characterized by different colors (one black and the other transparent). The study starts with the examination of each polymeric material and measurements of its main thermal properties.

  20. Preparation of Chitin-PLA laminated composite for implantable application.

    Science.gov (United States)

    Nasrin, Romana; Biswas, Shanta; Rashid, Taslim Ur; Afrin, Sanjida; Jahan, Rumana Akhter; Haque, Papia; Rahman, Mohammed Mizanur

    2017-12-01

    The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA) laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1-20% of PLA) reinforced PLA films (CTP) were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP) were prepared by laminating PLA film (obtained by hot press method) with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA) showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2) and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa) and CTP2 film (8.83 MPa). After lamination of pure PLA and CTP2 film, the composite (LCTP) yielded 0.265-1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

  1. Preparation and characterization of collagen/PLA, chitosan/PLA, and collagen/chitosan/PLA hybrid scaffolds for cartilage tissue engineering.

    Science.gov (United States)

    Haaparanta, Anne-Marie; Järvinen, Elina; Cengiz, Ibrahim Fatih; Ellä, Ville; Kokkonen, Harri T; Kiviranta, Ilkka; Kellomäki, Minna

    2014-04-01

    In this study, three-dimensional (3D) porous scaffolds were developed for the repair of articular cartilage defects. Novel collagen/polylactide (PLA), chitosan/PLA, and collagen/chitosan/PLA hybrid scaffolds were fabricated by combining freeze-dried natural components and synthetic PLA mesh, where the 3D PLA mesh gives mechanical strength, and the natural polymers, collagen and/or chitosan, mimic the natural cartilage tissue environment of chondrocytes. In total, eight scaffold types were studied: four hybrid structures containing collagen and/or chitosan with PLA, and four parallel plain scaffolds with only collagen and/or chitosan. The potential of these types of scaffolds for cartilage tissue engineering applications were determined by the analysis of the microstructure, water uptake, mechanical strength, and the viability and attachment of adult bovine chondrocytes to the scaffolds. The manufacturing method used was found to be applicable for the manufacturing of hybrid scaffolds with highly porous 3D structures. All the hybrid scaffolds showed a highly porous structure with open pores throughout the scaffold. Collagen was found to bind water inside the structure in all collagen-containing scaffolds better than the chitosan-containing scaffolds, and the plain collagen scaffolds had the highest water absorption. The stiffness of the scaffold was improved by the hybrid structure compared to plain scaffolds. The cell viability and attachment was good in all scaffolds, however, the collagen hybrid scaffolds showed the best penetration of cells into the scaffold. Our results show that from the studied scaffolds the collagen/PLA hybrids are the most promising scaffolds from this group for cartilage tissue engineering.

  2. Transkateterlukning af venstre atriums aurikel til forebyggelse af apoplexia cerebri

    DEFF Research Database (Denmark)

    Loupis, Anastasia M; De Backer, Ole; Ihlemann, Nikolaj

    2014-01-01

    In patients with atrial fibrillation (AF) and increased risk of stroke, oral anticoagulation (OAC) is the standard treatment for stroke prevention - however, this therapy also carries a high risk of bleeding. Percutaneous closure of the left atrial appendage (LAA) has been suggested to be an alte...

  3. Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

    International Nuclear Information System (INIS)

    Nofar, M.; Heuzey, M. C.; Carreau, P. J.; Kamal, M. R.; Randall, J.

    2016-01-01

    Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s"−"1 at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s"−"1 induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

  4. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

    2008-01-01

    Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

  5. Creating a Positive Prior Learning Assessment (PLA Experience: A Step-by-Step Look at University PLA

    Directory of Open Access Journals (Sweden)

    Sara M. Leiste

    2011-01-01

    Full Text Available A prior learning assessment (PLA can be an intimidating process for adult learners. Capella University’s PLA team has developed best practices, resources, and tools to foster a positive experience and to remove barriers in PLA and uses three criteria to determine how to best administer the assessment. First, a PLA must be motivating, as described by the ARCS model. Second, it must enable success. Finally, it must use available resources efficiently. The tools and resources developed according to these criteria fall into two categories: staff and online resources. PLA programs can use both to ensure that all departments provide consistent communication to learners about the PLA process, which will foster a positive experience. The PLA online lab houses centralized resources and offers one-on-one interaction with a facilitator to assist learners step-by-step in the development of their petitions. Each unit contains resources, examples, and optional assignments that help learners to develop specific aspects of the petition. By following the examples and recommendations, learners are able to submit polished petitions after they complete the units. The lab facilitator supports learners throughout the units by answering questions and providing recommendations. When learners submit their petitions, the facilitator reviews it entirely and provides feedback to strengthen the final submission that goes to a faculty reviewer for an official evaluation. All of these individuals and tools work together to help create a positive experience for learners who submit a PLA petition. This article shares these resources with the goal of strengthening PLA as a field.

  6. Novel PLA-Based Conductive Polymer Composites for Biomedical Applications

    Science.gov (United States)

    Shah, Aziurah Mohd; Kadir, Mohammed Rafiq Abdul; Razak, Saiful Izwan Abd

    2017-12-01

    In this study, the electrical conductivity of polylactic acid (PLA)-based composites has been improved using polyaniline (PANI) with two different solvents: dodecylbenzene sulfonic acid and citric acid. The effects of various factors including PLA quantity, solvent concentration, type of solvent and thickness on the resistivity were investigated using the design of experiments. The experimental plan was based on irregular fraction design to develop the regression models. The results revealed that the proposed mathematical models were sufficient and could describe the performance of resistivity of PLA within the limits of a factor. The findings also indicated that thickness had the most significant effect on the resistivity of PLA, while the effect of the type of solvent was of least significance. Moreover, it was illustrated that, by incorporating two different solvents into PANI, the resistivity could be changed for further applications.

  7. China's Military Modernization: Redefining PLA Center of Gravity

    National Research Council Canada - National Science Library

    Palmer, Craig

    2001-01-01

    .... To achieve this desired influence, China is modernizing the PLA and planning for expansion of their operating area to a "green water" navy by early 21st century and a "blue water" navy by 2050...

  8. Chinese cyber espionage: a complementary method to aid PLA modernization

    OpenAIRE

    Ellis, Jamie M.

    2015-01-01

    Approved for public release; distribution is unlimited In 2013, Mandiant published a report linking one People’s Liberation Army (PLA) unit to the virtual exploitation of 11 modern U.S. military platforms. In the last two decades, Chinese cyber espionage has cultivated a significant reputation in cyberspace for its high-volume, illicit exploitation of defense technology. At the same time, the PLA has also rapidly modernized its naval, fighter jet, and air defense technologies. This thesis ...

  9. Activation of PLA2 isoforms by cell swelling and ischaemia/hypoxia

    DEFF Research Database (Denmark)

    Lambert, I. H.; Pedersen, S. F.; Poulsen, K. A.

    2006-01-01

    Phospholipase A2 (PLA2) activity is increased in mammalian cells in response to numerous stimuli such as osmotic challenge, oxidative stress and exposure to allergens. The increased PLA2 activity is seen as an increased release of free, polyunsaturated fatty acids, e.g. arachidonic acid....... Here, we review data that illustrates that stress-induced PLA2 activity involves various PLA2 subtypes and that the PLA2 in question is determined by the cell type and the physiological stress condition....

  10. Electrospinning synthesis and characterization of PLA-PEG-MNPs composite fibrous membranes

    Science.gov (United States)

    Kumar, M.; Klimke, S.; Preiss, A.; Unruh, D.; Wengerowsky, D.; Lehmann, R.; Sindelar, R.; Klingelhöfer, G.; Boča, R.; Renz, F.

    2017-11-01

    An electrospinning technique was used to fabricate PLA, PLA-PEG and PLA-PEG-MNPs composite fibrous membranes. The morphology of electrospun composite membranes were characterized by scanning electron microscope. To test the potential availability of MNPs in PLA-PEG composite membranes, TG, Raman, Mössbauer, VSM and ICP-OES analysis were used. The PLA-PEG composite fibrous membranes showed the presence of MNPs, hence offers the possibility for magnetically triggered on-demand drug delivery.

  11. Optimisation of Heating Energy Demand and Thermal Comfort of a Courtyard-Atrium Dwelling

    NARCIS (Netherlands)

    Taleghani, M.; Tenpierik, M.; Dobbelsteen, A.

    2013-01-01

    In the light of energy reduction, transitional spaces are recognised as ways to receive natural light and fresh air. This paper analyses the effects of courtyard and atrium as two types of transitional spaces on heating demand and thermal comfort of a Dutch low-rise dwelling, at current and future

  12. Thrombus Development on a Transseptal Sheath in the Right Atrium Before Electrical Pulmonary Vein Isolation

    Directory of Open Access Journals (Sweden)

    Nieves Romero-Rodriguez

    2008-02-01

    Full Text Available We describe the case of a patient who developed a thrombus on the transseptal sheath in the right atrium before transseptal puncture for circumferential pulmonary vein isolation for paroxysmal atrial fibrillation treatment. The use of intracardiac echocardiography allowed to its identification and probably prevented the patient from suffering a serious thromboembolic complication.

  13. Anatomical barriers in the right atrium to the coronary sinus cannulation

    Directory of Open Access Journals (Sweden)

    Wiesława Klimek-Piotrowska

    2016-01-01

    Full Text Available Background. The coronary venous system is an increasingly frequent target of minimally invasive cardiac procedures. The purpose of this paper is to assess the anatomical barriers in the right atrium to coronary sinus cannulation.Methods. We examined the anatomy of the right atrium, coronary sinus ostium, inferior and superior vena cava ostia in 110 randomly selected autopsied human hearts of both sexes (27% females; mean age 49.2 ± 17.5 years.Results. The Eustachian valve was present in 79 cases (71.8% with mean height =4.9 ± 2.6 mm. The valve was perforated in 11 cases (13.9%. It is typically too small to hinder the coronary sinus catheterization, but in some cases (about 2% a significantly protruding valve may be an obstacle. Chiari’s network (4.6% is not a barrier to catheter entry into the right atrium but may significantly impede further catheter manipulations inside the heart venous system. A typical Thebesian valve leaves enough space for the passage of the standard catheter to the coronary sinus.Discussion. Detailed anatomy of various anatomical structures within the right atrium that could play a potential role in coronary sinus cannulation is discussed.

  14. Anomalous muscle bundle in the right atrium; Implication to trans atrial device closure

    Directory of Open Access Journals (Sweden)

    Saji Philip

    2017-09-01

    Full Text Available Intracavitary muscle bands or aberrant bands have been well described in all four chambers of the heart but rarely seen thick muscular band crossing right atrium. We report a case of devisable secundum atrial septal defect with an intra-atrial anomalous muscular band, crossing right atrial wall to the rim of the secundum atrial septal defect warranting surgical closure.

  15. Rupture of sinus of Valsalva aneurysm into both right atrium and ...

    African Journals Online (AJOL)

    A young man had a congenital sinus of Valsalva aneurysm originating from the right coronary sinus, complicated by fistulas draining into both right atrium and right ventricle, as well as a congenitally abnormal aortic valve with mild aortic insufficiency. His dramatic clinical presentation, with the sudden appearance of severe ...

  16. Photocrosslinked PLA-PEO-PLA Hydrogels from Self-Assembled Physical Networks: Mechanical Properties and Influence of Assumed Constitutive Relationships

    OpenAIRE

    Sanabria-DeLong, Naomi; Crosby, Alfred J.; Tew, Gregory N.

    2008-01-01

    Poly(lactide) – block – poly(ethylene oxide) – block – poly(lactide) [PLA-PEO-PLA] triblock copolymers are known to form physical hydrogels in water, due to the polymer's amphiphilicity. Their mechanical properties, biocompatibility, and biodegradability have made them attractive for use as soft tissue scaffolds. However, the network junction points are not covalently crosslinked and in a highly aqueous environment these hydrogels adsorb more water, transform from gel to sol, and lose the des...

  17. Erratum to 'Surface Modification of PBO Fibers for Composites by Coaxial Atmospheric Dielectric Barrier Discharge (PLA-PLA)'

    International Nuclear Information System (INIS)

    2013-01-01

    There is a mistake in the funding number (National Natural Science Foundation of China (No. 10875146)) of article Surface Modification of PBO Fibers for Composites by Coaxial Atmospheric Dielectric Barrier Discharge (PLA-PLA), written by HU Qianqian, XU Jinzhou, ZHOU Zhenxing, ZHANG Jing, published in Plasma Science and Technology, 2013, Vol. 15, Issue 5, page number 429, it should be corrected as National Natural Science Foundation of China (No. 11075033). (erratum)

  18. Evaluation of self-assembled HCPT-loaded PEG-b-PLA nanoparticles by comparing with HCPT-loaded PLA nanoparticles.

    Science.gov (United States)

    Yang, Xiangrui; Wu, Shichao; Wang, Yange; Li, Yang; Chang, Di; Luo, Yin; Ye, Shefang; Hou, Zhenqing

    2014-12-01

    We present a dialysis technique to prepare the 10-hydroxycamptothecin (HCPT)-loaded nanoparticles (NPs) using methoxypolyethylene glycol-poly(D,L-lactide) (PEG-b-PLA) and PLA, respectively. Both HCPT-loaded PEG-b-PLA NPs and HCPT-loaded PLA NPs were characterized by differential scanning calorimetry (DSC), dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results showed that the HCPT-loaded PEG-b-PLA NPs and HCPT-loaded PLA NPs presented a hydrodynamic particle size of 120.1 and 226.8 nm, with a polydispersity index of 0.057 and 0.207, a zeta potential of -31.2 and -45.7 mV, drug encapsulation efficiency of 44.52% and 44.94%, and drug-loaded content of 7.42% and 7.49%, respectively. The HCPT-loaded PEG-b-PLA NPs presented faster drug release rate compared to the HCPT-loaded PLA NPs. The HCPT-loaded PEG-b-PLA NPs presented higher cytotoxicity than the HCPT-loaded PLA NPs. These results suggested that the HCPT-loaded PEG-b-PLA NPs presented better characteristics for drug delivery compared to HCPT-loaded PLA NPs.

  19. Kids in the atrium: comparing architectural intentions and children's experiences in a pediatric hospital lobby.

    Science.gov (United States)

    Adams, Annmarie; Theodore, David; Goldenberg, Ellie; McLaren, Coralee; McKeever, Patricia

    2010-03-01

    The study reported here adopts an interdisciplinary focus to elicit children's views about hospital environments. Based at the Hospital for Sick Children (SickKids), Toronto, the research explores the ways in which designers and patients understand and use the eight-storey lobby, The Atrium, a monumental addition constructed in 1993. It is a public place that never closes; hundreds of children pass through the namesake atrium every day. Combining methodological approaches from architectural history and health sociology, the intentions and uses of central features of the hospital atrium are examined. Data were collected from observations, focused interviews, and textual and visual documents. We locate the contemporary atrium in a historical context of building typologies rarely connected to hospital design, such as shopping malls, hotels and airports. We link the design of these multi-storey, glass-roofed spaces to other urban experiences especially consumption as normalizing forces in the everyday lives of Canadian children. Seeking to uncover children's self-identified, self-articulated place within contemporary pediatric hospitals, we assess how the atrium--by providing important, but difficult-to-measure functions such as comfort, socialization, interface, wayfinding, contact with nature and diurnal rhythms, and respite from adjacent medicalized spaces--contributes to the well-being of young patients. We used theoretical underpinnings from architecture and humanistic geography, and participatory methods advocated by child researchers and theorists. Our findings begin to address the significant gap in understanding about the relationship between the perceptions of children and the settings where their healthcare occurs. The study also underlines children's potential to serve as agents of architectural knowledge, reporting on and recording their observations of hospital architecture with remarkable sophistication. 2009 Elsevier Ltd. All rights reserved.

  20. Preparation and Mechanical Properties of Fiber Reinforced PLA for 3D Printing Materials

    Science.gov (United States)

    Li, Xionghao; Ni, Zhongjin; Bai, Shuyang; Lou, Baiyang

    2018-03-01

    The cellulose prepared by means of TEMPO oxidation method and glass fibre was blended with PLA respectively, and were spun into enhanced PLA wires. This study evaluates the wire rods that is from extruder is suitable for FDM printing by various physical characterization tests to determine their feasibility as a 3D printing filament materials. The cellulose and glass fibre is blended with PLA and spun into the reinforced PLA filament respectively, which is applied to FDM printing technology. The results showed that the intensity of strike resistant of the reinforced PLA filament made from cellulose and PLA is 34% to 60% higher than the PLA filament, meanwhile the tensile strength is 43% to 52% higher than the pure one. The other enhanced PLA filament is 13% to 35% higher than the PLA filament in intensity of strike resistant, and the tensile strength is 54% to 61% higher than the pure one.

  1. Plain chest PA evaluation of left atrial thrombosis in mitral valvular disease

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Yeon Myung; Park, Jae Hyung; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1984-09-15

    Conventional posteroanterior chest radiographs of 73 patients with mitral valve disease who had had surgery were analyzed, and particular attention was directed to the absence of the convexity of the left lower mid cardiac border (left atrial segment) and to the relation with duration of illness, atrial fibrillation, pulmonary capillary wedge pressure (PCWP) as well as surgical findings. The results obtained are as follows: 1. The flatness or concavity of this segment, despite other evidence of left atrial enlargement, was observed in eleven (64.7%) of 17 patients who had left atrial thrombosis and in six (10.7%) of 56 patients who did not have thrombosis (false positive diagnosis). Six (35.5%) of the 17 patients who had left atrial thrombosis did not this findings on radiographs (false positive diagnosis). Six (35.3%) of the 17 patients who had left atrial thrombosis did not show this finding on radiographs (false positive diagnosis). Therefore, the accuracy in the diagnosis of thrombosis of left atrium wa 64.7% (eleven of seventeen) for patients who had thrombosis of left atrium. 2. The atrial fibrillation was observed in sixteen (94.1%)of 17 patients who had left atrial thrombosis. So, correlation between the presence of left atrial thrombosis and atrial fibrillation wa evident. But there was no correlation between the duration of illness of the PCWP of patients and the presence of left atrial thrombosis.

  2. Plain chest PA evaluation of left atrial thrombosis in mitral valvular disease

    International Nuclear Information System (INIS)

    Choo, Yeon Myung; Park, Jae Hyung; Han, Man Chung

    1984-01-01

    Conventional posteroanterior chest radiographs of 73 patients with mitral valve disease who had had surgery were analyzed, and particular attention was directed to the absence of the convexity of the left lower mid cardiac border (left atrial segment) and to the relation with duration of illness, atrial fibrillation, pulmonary capillary wedge pressure (PCWP) as well as surgical findings. The results obtained are as follows: 1. The flatness or concavity of this segment, despite other evidence of left atrial enlargement, was observed in eleven (64.7%) of 17 patients who had left atrial thrombosis and in six (10.7%) of 56 patients who did not have thrombosis (false positive diagnosis). Six (35.5%) of the 17 patients who had left atrial thrombosis did not this findings on radiographs (false positive diagnosis). Six (35.3%) of the 17 patients who had left atrial thrombosis did not show this finding on radiographs (false positive diagnosis). Therefore, the accuracy in the diagnosis of thrombosis of left atrium wa 64.7% (eleven of seventeen) for patients who had thrombosis of left atrium. 2. The atrial fibrillation was observed in sixteen (94.1%)of 17 patients who had left atrial thrombosis. So, correlation between the presence of left atrial thrombosis and atrial fibrillation wa evident. But there was no correlation between the duration of illness of the PCWP of patients and the presence of left atrial thrombosis.

  3. Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Nofar, M. [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4, Canada and CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Heuzey, M. C.; Carreau, P. J., E-mail: pierre.carreau@polymtl.ca [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4 (Canada); Kamal, M. R. [CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Randall, J. [NatureWorks LLC, 15305 Minnetonka Boulevard, Minnetonka, Minnesota 55345 (United States)

    2016-07-15

    Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s{sup −1} at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s{sup −1} induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

  4. Homocomposites of Polylactide (PLA) with Induced Interfacial Stereocomplex Crystallites

    Science.gov (United States)

    2015-01-01

    The demand for “green” degradable composite materials increases with growing environmental awareness. The key challenge is achieving the preferred physical properties and maintaining their eco-attributes in terms of the degradability of the matrix and the filler. Herein, we have designed a series of “green” homocomposites materials based purely on polylactide (PLA) polymers with different structures. Film-extruded homocomposites were prepared by melt-blending PLA matrixes (which had different degrees of crystallinity) with PLLA and PLA stereocomplex (SC) particles. The PLLA and SC particles were spherical and with 300–500 nm size. Interfacial crystalline structures in the form of stereocomplexes were obtained for certain particulate-homocomposite formulations. These SC crystallites were found at the particle/matrix interface when adding PLLA particles to a PLA matrix with d-lactide units, as confirmed by XRD and DSC data analyses. For all homocomposites, the PLLA and SC particles acted as nucleating agents and enhanced the crystallization of the PLA matrixes. The SC particles were more rigid and had a higher Young’s modulus compared with the PLLA particles. The mechanical properties of the homocomposites varied with particle size, rigidity, and the interfacial adhesion between the particles and the matrix. An improved tensile strength in the homocomposites was achieved from the interfacial stereocomplex formation. Hereafter, homocomposites with tunable crystalline arrangements and subsequently physical properties, are promising alternatives in strive for eco-composites and by this, creating materials that are completely degradable and sustainable. PMID:26523245

  5. Morphology control of PLA microfibers and spheres via melt electrospinning

    Science.gov (United States)

    Yu, Shu-Xin; Zheng, Jie; Yan, Xu; Wang, Xiao-Xiong; Nie, Guang-Di; Tan, Ye-Qiang; Zhang, Jun; Sui, Kun-Yan; Long, Yun-Ze

    2018-04-01

    In conventional solution electrospinning, the morphologies (e.g., spheres, beaded fibers, and fibers) of electrospun products can be controlled by solution concentration. Here, we report that the morphologies and structures of polylactic acid (PLA) via melt electrospinning also can be adjusted from microfibers to microspheres by simply increasing the spinning temperature. It was found that with temperature increasing from 200 °C to 240 °C, the average diameter of melt-electrospun PLA fibers decreased from 58.46 to 2.96 μm. Then, beaded fibers and microspheres about 14.5 μm in diameter were collected when the spinning temperature was increased to 250 °C and 260 °C. In addition, we also found that the average PLA fiber diameter decreased with increasing the applied spinning voltage, and increased with the increase of spinning distance. To explain the formation mechanism of different PLA microstructures, rheological property and infrared spectra of PLA under different spinning temperatures were also tested.

  6. Aqueous leaf extract of Averrhoa carambola L. (Oxalidaceae reduces both the inotropic effect of BAY K 8644 on the guinea pig atrium and the calcium current on GH3cells

    Directory of Open Access Journals (Sweden)

    Carla M. L. Vasconcelos

    Full Text Available It was previously showed that aqueous leaf extract (AqEx of Averrhoa carambola depresses the guinea pig atrial inotropism. Therefore, experiments were carried out on guinea pig left atrium and on pituitary GH3 cells in order to evaluate the effect of AqEx on the cellular calcium influx. The atrium was mounted in an organ chamber (5 mL, Tyrode, 27 ± 0.1 ºC, 95 % O2, 5 % CO2, stretched to 10 mN, and paced at 2 Hz (0.5 ms, 400 V and GH3 cells were submitted to a whole cell voltage clamp configuration. In the atrium, the AqEx (1500 µg/mL shifted to the right the concentration-effect curve of the positive inotropic effect produced by (± BAY K 8644, an L-type calcium channel agonist. The AqEx increased EC50 (concentration required to promote 50% of the maximum effect of the inotropic effect of BAY K 8644 from 7.8 ± 0.38 to 115.1 ± 0.44 nM (N = 3; p < 0.05. In GH3 cells assayed with 500 µg/mL of AqEx, the L-type calcium inward current declined 30 % (from 282 to 190 pA. Nevertheless, the extract did not change the voltage correspondent to the peak current. These data suggest that, at least in part, the negative inotropic effect of AqEx on the guinea pig atrium is due to a reduction of the L-type calcium current.

  7. Evaluation of right atrium-to-right ventricle diameter ratio on computed tomography pulmonary angiography: Prediction of adverse outcome and 30-day mortality.

    Science.gov (United States)

    Oz, Ibrahim Ilker; Altınsoy, Bülent; Serifoglu, Ismail; Sayın, Rasit; Buyukuysal, Mustafa Cagatay; Erboy, Fatma; Akduman, Ece Isin

    2015-12-01

    The aim of this study was to examine the association between right atrium (RA) and right ventricle (RV) diameters on computed tomography (CT) pulmonary angiography in response to acute pulmonary embolism (APE), in addition to 30-day mortality and adverse outcomes in patients with APE. This retrospective study was accepted by the institutional ethics committee. From January 2013 to March 2014, 79 hospitalized adult patients with symptomatic APE were included. Inclusion criteria were a CT pulmonary angiography positive for pulmonary embolism, availability of patient records, and a follow-up of at least 30 days. A review of patient records and images was performed. The maximum diameters of the heart chambers were measured on a reconstructed four-chamber heart view, and the vascular obstruction index was calculated on CT pulmonary angiography. There were statistically significant relationships in both the RA/RV diameter ratio and the RV/left ventricle (LV) diameter ratio between patients with and without adverse outcomes (prights reserved.

  8. Anti-cancer evaluation of quercetin embedded PLA nanoparticles synthesized by emulsified nanoprecipitation.

    Science.gov (United States)

    Pandey, Sanjeev K; Patel, Dinesh K; Thakur, Ravi; Mishra, Durga P; Maiti, Pralay; Haldar, Chandana

    2015-04-01

    This study was carried out to synthesize quercetin (Qt) embedded poly(lactic acid) (PLA) nanoparticles (PLA-Qt) and to evaluate anti-cancer efficacy of PLA-Qt by using human breast cancer cells. PLA-Qt were synthesized by using novel emulsified nanoprecipitation technique with varying dimension of 32 ± 8 to 152 ± 9 nm of PLA-Qt with 62 ± 3% (w/w) entrapment efficiency by varying the concentration of polymer, emulsifier, drug and preparation temperature. The dimension of PLA-Qt was measured through transmission electron microscopy indicating larger particle size at higher concentration of PLA. The release rate of Qt from PLA-Qt was found to be more sustained for larger particle dimension (152 ± 9 nm) as compared to smaller particle dimension (32 ± 8 nm). Interaction between Qt and PLA was verified through spectroscopic and calorimetric methods. Delayed diffusion and stronger interaction in PLA-Qt caused the sustained delivery of Qt from the polymer matrix. In vitro cytotoxicity study indicate the killing of ∼ 50% breast cancer cells in two days at 100 μg/ml of drug concentration while the ∼ 40% destruction of cells require 5 days for PLA-Qt (46 ± 6 nm; 20mg/ml of PLA). Thus our results propose anticancer efficacy of PLA-Qt nanoparticles in terms of its sustained release kinetics revealing novel vehicle for the treatment of cancer. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Composite porous scaffold of PEG/PLA support improved bone matrix deposition in vitro compared to PLA-only scaffolds.

    Science.gov (United States)

    Bhaskar, Birru; Owen, Robert; Bahmaee, Hossein; Wally, Zena; Sreenivasa Rao, Parcha; Reilly, Gwendolen C

    2018-05-01

    Controllable pore size and architecture are essential properties for tissue-engineering scaffolds to support cell ingrowth colonization. To investigate the effect of polyethylene glycol (PEG) addition on porosity and bone-cell behavior, porous polylactic acid (PLA)-PEG scaffolds were developed with varied weight ratios of PLA-PEG (100/0, 90/10, 75/25) using solvent casting and porogen leaching. Sugar 200-300 µm in size was used as a porogen. To assess scaffold suitability for bone tissue engineering, MLO-A5 murine osteoblast cells were cultured and cell metabolic activity, alkaline phosphatase (ALP) activity and bone-matrix production determined using (alizarin red S staining for calcium and direct red 80 staining for collagen). It was found that metabolic activity was significantly higher over time on scaffolds containing PEG, ALP activity and mineralized matrix production were also significantly higher on scaffolds containing 25% PEG. Porous architecture and cell distribution and penetration into the scaffold were analyzed using SEM and confocal microscopy, revealing that inclusion of PEG increased pore interconnectivity and therefore cell ingrowth in comparison to pure PLA scaffolds. The results of this study confirmed that PLA-PEG porous scaffolds support mineralizing osteoblasts better than pure PLA scaffolds, indicating they have a high potential for use in bone tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1334-1340, 2018. © 2018 Wiley Periodicals, Inc.

  10. Mechanical behaviour׳s evolution of a PLA-b-PEG-b-PLA triblock copolymer during hydrolytic degradation.

    Science.gov (United States)

    Breche, Q; Chagnon, G; Machado, G; Girard, E; Nottelet, B; Garric, X; Favier, D

    2016-07-01

    PLA-b-PEG-b-PLA is a biodegradable triblock copolymer that presents both the mechanical properties of PLA and the hydrophilicity of PEG. In this paper, physical and mechanical properties of PLA-b-PEG-b-PLA are studied during in vitro degradation. The degradation process leads to a mass loss, a decrease of number average molecular weight and an increase of dispersity index. Mechanical experiments are made in a specific experimental set-up designed to create an environment close to in vivo conditions. The viscoelastic behaviour of the material is studied during the degradation. Finally, the mechanical behaviour is modelled with a linear viscoelastic model. A degradation variable is defined and included in the model to describe the hydrolytic degradation. This variable is linked to physical parameters of the macromolecular polymer network. The model allows us to describe weak deformations but become less accurate for larger deformations. The abilities and limits of the model are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. THE COMPARISON BETWEEN COMPUTER SIMULATION AND PHYSICAL MODEL IN CALCULATING ILLUMINANCE LEVEL OF ATRIUM BUILDING

    Directory of Open Access Journals (Sweden)

    Sushardjanti Felasari

    2003-01-01

    Full Text Available This research examines the accuracy of computer programmes to simulate the illuminance level in atrium buildings compare to the measurement of those in physical models. The case was taken in atrium building with 4 types of roof i.e. pitched roof, barrel vault roof, monitor pitched roof (both monitor pitched roof and monitor barrel vault roof, and north light roof (both with north orientation and south orientation. The results show that both methods have agreement and disagreement. They show the same pattern of daylight distribution. In the other side, in terms of daylight factors, computer simulation tends to underestimate calculation compared to physical model measurement, while for average and minimum illumination, it tends to overestimate the calculation.

  12. Design of an atrium for a passive-solar retrofit of an office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J.L.; Hunn, B.D.

    1980-01-01

    The Los Alamos Scientific Laboratory (LASL) has proposed to retrofit one of its administrative office buildings with a solar atrium. A 334 m/sup 2/ courtyard will be enclosed with a roof-mounted system of clerestory windows to maximize winter solar gain. This sunspace will thermally buffer the adjoining offices and also will preheat air supplied to the building's conventional heating, ventilating, and air-conditioning (HVAC) system. The use of the DOE-2 building energy analysis computer program in the design of the solar atrium is described. The results of a series of simulations are reported detailing the tradeoffs inherent in the selection of an optimal glazing area, the maintenance of acceptable comfort levels within the sunspace, and intergration of passive-solar devices with the conventional HVAC system. Potential energy savings are also discussed.

  13. Mapping of the left-sided phrenic nerve course in patients undergoing left atrial catheter ablations.

    Science.gov (United States)

    Huemer, Martin; Wutzler, Alexander; Parwani, Abdul S; Attanasio, Philipp; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

    2014-09-01

    Catheter ablation of atrial fibrillation has been associated with left-sided phrenic nerve palsy. Knowledge of the individual left phrenic nerve course therefore is essential to prevent nerve injury. The aim of this study was to test the feasibility of an intraprocedural pace mapping and reconstruction of the left phrenic nerve course and to characterize which anatomical areas are affected. In patients undergoing left atrial catheter ablation, a three-dimensional map of the left atrial anatomical structures was created. The left-sided phrenic nerve course was determined by high-output pace mapping and reconstructed in the map. In this study, 40 patients with atrial fibrillation or atrial tachycardias were included. Left phrenic nerve capture was observed in 23 (57.5%) patients. Phrenic nerve was captured in 22 (55%) patients inside the left atrial appendage, in 22 (55%) in distal parts, in 21 (53%) in medial parts, and in two (5%) in ostial parts of the appendage. In three (7.5%) patients, capture was found in the distal coronary sinus and in one (2.5%) patient in the left atrium near the left atrial appendage ostium. Ablation target was changed due to direct spatial relationship to the phrenic nerve in three (7.5%) patients. No phrenic nerve palsy was observed. Left-sided phrenic nerve capture was found inside and around the left atrial appendage in the majority of patients and additionally in the distal coronary sinus. Phrenic nerve mapping and reconstruction can easily be performed and should be considered prior catheter ablations in potential affected areas. ©2014 Wiley Periodicals, Inc.

  14. Atypical leiomyoma arising in a hepatic vein with extension into the inferior vena cava and right atrium

    International Nuclear Information System (INIS)

    Dunlap, H.J.; Udjus, K.

    1990-01-01

    We report an atypical leiomyoma arising in a hepatic vein and extending into the inferior vena cava and right atrium in a fourteen year old boy. US, CT and MRI facilitated diagnosis and removal of this tumor. (orig.)

  15. Unusual Giant Right Atrium in Rheumatic Mitral Stenosis and Tricuspid Insufficiency

    Directory of Open Access Journals (Sweden)

    Jean Baptiste Anzouan-Kacou

    2011-01-01

    Full Text Available Dilation and hypertrophy of the atria occur in patients with valvular heart disease especially in mitral regurgitation, mitral stenosis or tricuspid abnormalities. In sub-saharan Africa, rheumatic fever is still the leading cause of valvular heart disease. We report a case of an unusual giant right atrium in context of rheumatic stenosis and severe tricuspid regurgitation in a 58-year-old woman.

  16. A case report: mixed thrombus formation in a previously sutured right atrium.

    Science.gov (United States)

    Yunfei, Ling; Dongxu, Li; Shuhua, Luo; Yabo, Wang; San, Deep; Changping, Gan; Ke, Lin; Qi, An

    2014-08-01

    We describe the case of a 19-year-old Chinese woman who nine months prior underwent repair of an atrial septal defect and came to our hospital with a right atrial mass attached to the anterior wall of the right atrium on transthoracic echocardiography. Pathologic examination revealed the mass was a mixed-type thrombosis with some unusual organization, which previously was not described in literature.

  17. Il patrimonio scomodo del Novecento europeo nel progetto Atrium a Forlì

    Directory of Open Access Journals (Sweden)

    Elena Pirazzoli

    2013-09-01

    Full Text Available Il Novecento ha lasciato tracce difficili nelle città d'Europa. I regimi che si sono succeduti hanno trasformato urbanisticamente e architettonicamente l'intero territorio e oggi è complesso relazionarsi con questi segni. Il progetto europeo Atrium - Architecture of Totalitarian Regimes in Urban Managements si propone di valorizzare, con attenta cura e senza intenti mistificatori, proprio il “patrimonio scomodo” di 11 paesi dell'Europa del sud.

  18. Renal Angiomyolipoma with Fatty Thrombus Extending to the Right Atrium: An Exceptional Presentation

    Directory of Open Access Journals (Sweden)

    Yassine Nouira

    2013-01-01

    Full Text Available This paper reports the case of 34-year-old woman who presented with bilateral renal angiomyolipomas (AMLs. On the right side, there was a large AML with a fatty thrombus extending to the right atrium. The treatment consisted of right nephrectomy and complete thrombectomy with extracorporeal circulation and right atriotomy. Postoperatively, the patient was septic and died on postoperative day 7 because of septic shock.

  19. Effect of PlA1/A2 glycoprotein IIIa gene polymorphism on the long-term outcome after successful coronary stenting

    Directory of Open Access Journals (Sweden)

    Riddell John

    2007-11-01

    Full Text Available Abstract Aim To prospectively determine the role of platelet glycoprotein IIIa (GP IIIa gene PlA1/PlA2 polymorphism on the long-term clinical outcome in patients with coronary artery disease undergoing coronary stenting. Design and setting Prospective observational study in the University Hospital of Caen (France. Patients and methods 1 111 symptomatic consecutive Caucasian patients treated with percutaneous coronary intervention including stent implantation underwent genotyping for GP IIIa PlA1/A2. Main outcome measures Long-term clinical outcome in terms of the rate of major adverse cardiac events (MACE, ie death from any cause, non-fatal Q wave or non Q wave myocardial infarction, and need for coronary revascularisation was obtained and subsequently stratified according to the GP IIIa PlA1/A2 polymorphism. Results Three groups of patients were determined according to the GP IIIa PlA1/A2 polymorphism (71.6% had the A1/A1, 25.8% had the A1/A2 and 2.6% had the A2/A2 genotype. These three groups were comparable for all clinical characteristics including sex ratio, mean age, vascular risk factors, previous coronary events, baseline angiographic exam, indication for the percutaneous coronary intervention and drug therapy. The incidence of MACE was similar in these 3 groups of patients during a mean follow-up period of 654+/-152 days. Independent risk factors for MACE were a left ventricular ejection fraction Conclusion The GP IIIa PlA1/A2 polymorphism does not influence the clinical long-term outcome in patients with symptomatic coronary disease undergoing percutaneous coronary intervention with stent implantation.

  20. Exploring the 'Right Size' for China's Military: PLA Missions, Functions, and Organizations

    National Research Council Canada - National Science Library

    Liang, Justin B; Snyder, Sarah K

    2007-01-01

    Key Points: *Sustained and large increases in China's People's Liberation Army (PLA) defense budget are likely in coming years as increasing national-level demands for new PLA missions require increasing capability...

  1. Researching for sustained translation from site cluster permeability into building courtyard and interior atrium

    Science.gov (United States)

    Teddy Badai Samodra, FX; Defiana, Ima; Setyawan, Wahyu

    2018-03-01

    Many previous types of research have discussed the permeability of site cluster. Because of interaction and interconnected attribute, it will be better that there is its translation into lower context such as building and interior scale. In this paper, the sustainability design performance of both similar designs of courtyard and atrium are investigated continuing the recommendation of site space permeability. By researching related literature review and study through Ecotect Analysis and Ansys Fluent simulations, the pattern transformation and optimum courtyard and atrium design could comply the requirement. The results highlighted that the air movement from the site could be translated at the minimum of 50% higher to the building and indoor environment. Thus, it has potency for energy efficiency when grid, loop, and cul-de-sac site clusters, with 25% of ground coverage, have connectivity with building courtyard compared to the atrium. Energy saving is higher when using low thermal transmittance of transparent material and its lower area percentages for the courtyard walls. In general, it was more energy efficient option as part of a low rise building, while the courtyard building performed better with increasing irregular building height more than 90% of the difference.

  2. Identification of a novel antisense long non-coding RNA PLA2G16-AS that regulates the expression of PLA2G16 in pigs.

    Science.gov (United States)

    Liu, Pengliang; Jin, Long; Zhao, Lirui; Long, Keren; Song, Yang; Tang, Qianzi; Ma, Jideng; Wang, Xun; Tang, Guoqing; Jiang, Yanzhi; Zhu, Li; Li, Xuewei; Li, Mingzhou

    2018-05-31

    Natural antisense transcripts (NATs) are widely present in mammalian genomes and act as pivotal regulator molecules to control gene expression. However, studies on the NATs of pigs are relatively rare. Here, we identified a novel antisense transcript, designated PLA2G16-AS, transcribed from the phospholipase A2 group XVI locus (PLA2G16) in the porcine genome, which is a well-known regulatory molecule of fat deposition. PLA2G16-AS and PLA2G16 were dominantly expressed in porcine adipose tissue, and were differentially expressed between Tibetan pigs and Rongchang pigs. In addition, PLA2G16-AS has a weak sequence conservation among different vertebrates. PLA2G16-AS was also shown to form an RNA-RNA duplex with PLA2G16, and to regulate PLA2G16 expression at the mRNA level. Moreover, the overexpression of PLA2G16-AS increased the stability of PLA2G16 mRNA in porcine cells. We envision that our findings of a NAT for a regulatory gene associated with lipolysis might further our understanding of the molecular regulation of fat deposition. Copyright © 2017. Published by Elsevier B.V.

  3. Novel scaffold design with multi-grooved PLA fibers

    International Nuclear Information System (INIS)

    Chung, Sangwon; King, Martin W; Gamcsik, Mike P

    2011-01-01

    A novel prototype nonwoven textile structure containing polylactide (PLA) multigrooved fibers has been proposed as a possible scaffold material for superior cell attachment and proliferation. Grooved cross-sectional fibers with larger surface area were obtained by a bi-component spinning system and the complete removal of the sacrificial component was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and x-ray photon spectroscopy (XPS) analysis. These PLA nonwoven scaffolds containing the grooved fibers exhibited enhanced wettability, greater flexibility and tensile properties, and a larger surface area compared to a traditional PLA nonwoven fabric containing round fibers. To evaluate cellular attachment on the two types of PLA nonwoven scaffolds, NIH 3T3 fibroblasts were cultured for up to 12 days. It was evident that the initial cellular attachment was superior on the scaffold with grooved fibers, which was confirmed by MTT viability assay (p < 0.01) and SEM analysis. In the future, by modulating the size of the grooves on the fibers, such a scaffold material with a large surface area could serve as an alternative matrix for culturing different types of cells.

  4. Texas A&M Texarkana Illustrates Best Practices in PLA

    Science.gov (United States)

    Delleville, Valerie

    2017-01-01

    Some institutions' prior learning assessment (PLA) programs are far more successful than others. As with any strategic initiative, the best-intentioned policy is only as good as the implementation, operations, and people behind it. Beyond progressing through the change management process, ensuring sustainability is critical to long-term PLA…

  5. All Work and No PLA Makes Jack a Dull Boy

    Science.gov (United States)

    Popova-Gonci, Viktoria

    2009-01-01

    In this article, the author presents an assortment of approaches--building blocks--commonly used in Prior Learning Assessment (PLA) practices (this list is certainly not comprehensive): (1) course matching (comparing course requirements to a student's prior learning experiences); (2) student's ability to articulate learning gained from…

  6. Implantation of a cardiac resynchronization therapy-defibrillator device in a patient with persistent left superior vena cava.

    Science.gov (United States)

    Atar, İlyas; Karaçağlar, Emir; Özçalık, Emre; Özin, Bülent; Müderrisoğlu, Haldun

    2015-06-01

    Presence of a persistent left superior vena cava (PLSVC) is generally clinically asymptomatic and discovered incidentally during central venous catheterization. However, PLSVC may cause technical difficulties during cardiac device implantation. An 82-year-old man with heart failure symptoms and an ejection fraction (EF) of 20% was scheduled for resynchronization therapy-defibrillator device (CRT-D) implantation. A PLSVC draining via a dilated coronary sinus into an enlarged right atrium was diagnosed. First, an active-fixation right ventricular lead was inserted into the right atrium through the PLSVC. The stylet was preshaped to facilitate its passage to the right ventricular apex. An atrial lead was positioned on the right atrium free wall, and an over-the-wire coronary sinus lead deployed to a stable position. CRT-D implantation procedure was successfully completed.

  7. Association Between Left Atrial Compression And Atrial Fibrillation: A Case Presentation And A Short Review Of Literature.

    Science.gov (United States)

    Ahmed, Niloy; Carlos, Morales-Mangual; Moshe, Gunsburg; Yitzhak, Rosen

    2016-01-01

    This case report describes a patient who developed palpitations and chest pain and was found to be in atrial fibrillation, which was likely due to the presence of an extra-cardiac mass. This was compressing the left atrium. The mass was related to small cell carcinoma, which decreased significantly in size after chemotherapy. Resolution of the atrial fibrillation correlated temporally with reduction in the size of the mass and alleviation of the left atrial compression.

  8. Plasma Lp-PLA2 mass and apoB-lipoproteins that carry Lp-PLA2 decrease after sodium

    NARCIS (Netherlands)

    Constantinides, Alexander; Kerstens, Michiel N.; Dikkeschei, Bert D.; van Pelt, L. Joost; Tellis, Constantinos C.; Tselepis, Alexandros D.; Dullaart, Robin P. F.

    2012-01-01

    Eur J Clin Invest 2012; 42 (11): 12351243 Abstract Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a novel cardiovascular risk marker, which is predominantly complexed to apolipoprotein (apo) B-containing lipoproteins in human plasma. As increasing dietary sodium intake may decrease

  9. Primerjalna analiza obdavčitve managerskih plač v Sloveniji in Veliki Britaniji

    OpenAIRE

    Janković, Nataša

    2016-01-01

    Vsak zaposleni dobi za opravljeno delo plačilo. Plača predstavlja motivacijski dejavnik in večja kot je odgovornost na delovnem mestu, višji je tudi dohodek. Managerji zaradi narave dela, ki ga opravljajo, sodijo v skupino posameznikov z nadpovprečnimi dohodki. Plača je sestavljena iz fiksnega in variabilnega dela. Fiksni del predstavlja osnovno plačo, ki je določena glede na zahtevnost dela, variabilni del pa sestavljajo nagrade in plačilo za uspešnost. Pri vsakem izplačilu delodajalec od pl...

  10. LEFT ATRIAL FIBROSIS IN PATIENTS WITH ATRIAL FIBRILLATION ACCORDING TO MAGNETIC RESONANCE IMAGING WITH LATE GADOLINIUM ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    O. V. Stukalova

    2015-01-01

    Full Text Available Rationale: Atrial fibrillation (AF is the most common type of arrhythmia. Left atrial abnormalities in AF require further investigation.Aim: To evaluate characteristics of myocardial structure of the left atrium by magnetic resonance imaging (MRI with delayed contrast enhancement in patients with AF associated with essential hypertension (EH, in those without any cardiovascular disorders, and in patients with AF after cryoablation of the pulmonary artery orifice.Materials and methods: The study enrolled 53 patients with AF (mean age 56 years. Twenty eight of them had AF without any associated cardiovascular disorders (lone AF, or LAF group, 25 patients had AF related to EH (AF + EH group. Three patients had undergone anti-arrhythmic intervention. Cardiac MRI was performed in all patients with high resolution late gadolinium enhancement (LGE at 15–20 min after i.v. gadoversetamide (0.15 mmol/kg. For LGE MRI, we used a novel high resolution inversion recovery (inversion times 290–340 ms magnetic resonance pulse sequence with isotropic voxel (size 1.25 . 1.25 .2.5 mm and fat saturation. Left atrium walls were segmented semi-automatically on the LGE images. Left atrium fibrosis quantification was performed with the original software LGE Heart Analyzer, developed in Russian Cardiology Research and Production Complex (Moscow.Results: Left atrium fibrosis (mean, 9 [1.7; 18] % was found both in patients with AF + EH and with lone AF. There was a trend towards more significant left atrial fibrosis in the group of AF + EH, compared to that in the lone AF group (10.972 [6.98; 19.366] % vs 4.37 [0.893; 18.575] %, respectively, p = 0.1. The extent of left atrium fibrosis correlated with left atrium dilatation (r = 0.37, p < 0.001 and with the decreased ejection fraction (r = -0.4, р < 0.001. The patients who had undergone an antiarrhythmic intervention, demonstrated formation of intensive LGE zones in the ablation areas.Conclusion: Quantification of

  11. Spectral Doppler interrogation of the patent foramen ovale-a window to left heart hemodynamics.

    Science.gov (United States)

    Fadel, Bahaa M; Husain, Aysha; Bakarman, Hatem; Dahdouh, Ziad; Salvo, Giovanni Di; Mohty, Dania

    2015-02-01

    Spectral Doppler interrogation of flow across a patent foramen ovale (PFO) allows recording of the instantaneous pressure gradient between left and right atrium (RA). The assessment of RA pressure using the size and collapsibility of the inferior vena cava would thus allow estimation of left atrial (LA) pressure. In this article, we illustrate the value of spectral Doppler interrogation of flow across the PFO by transthoracic echocardiography as a novel and simple tool for the assessment of LA pressure and left cardiac hemodynamics in addition to the conventional noninvasive parameters. © 2014, Wiley Periodicals, Inc.

  12. Isolated left-sided partial anomalous pulmonary venous connection in a child.

    Science.gov (United States)

    Onan, İsmihan Selen; Sen, Onur; Gökalp, Selman; Onan, Burak

    2017-09-01

    Isolated left-sided partial anomalous pulmonary venous connection with intact interatrial septum is a rare diagnosis in childhood. In these cases, a vertical vein drains the left upper pulmonary lobe into the brachiocephalic vein and finally to the right atrium. Surgical treatment is performed to prevent right ventricular failure and pulmonary artery disease in advanced age. In this report, the rare entity of isolated left-sided anomalous pulmonary venous connection in a 14-year-old girl and successful minimally invasive surgery without cardiopulmonary bypass are described.

  13. Synthesis of protein-coated biocompatible methotrexate-loaded PLA-PEG-PLA nanoparticles for breast cancer treatment

    Directory of Open Access Journals (Sweden)

    Salam Massadeh

    2016-06-01

    Full Text Available Background: PLA-PEG-PLA triblock polymer nanoparticles are promising tools for targeted dug delivery. The main aim in designing polymeric nanoparticles for drug delivery is achieving a controlled and targeted release of a specific drug at the therapeutically optimal rate and choosing a suitable preparation method to encapsulate the drug efficiently, which depends mainly on the nature of the drug (hydrophilic or hydrophobic. In this study, methotrexate (MTX-loaded nanoparticles were prepared by the double emulsion method. Method: Biodegradable polymer polyethylene glycol-polylactide acid tri-block was used with poly(vinyl alcohol as emulsifier. The resulting methotrexate polymer nanoparticles were coated with bovine serum albumin in order to improve their biocompatibility. This study focused on particle size distribution, zeta potential, encapsulation efficiency, loading capacity, and in vitro drug release at various concentrations of PVA (0.5%, 1%, 2%, and 3%. Results: Reduced particle size of methotrexate-loaded nanoparticles was obtained using lower PVA concentrations. Enhanced encapsulation efficiency and loading capacity was obtained using 1% PVA. FT-IR characterization was conducted for the void polymer nanoparticles and for drug-loaded nanoparticles with methotrexate, and the protein-coated nanoparticles in solid state showed the structure of the plain PEG-PLA and the drug-loaded nanoparticles with methotrexate. The methotrexate-loaded PLA-PEG-PLA nanoparticles have been studied in vitro; the drug release, drug loading, and yield are reported. Conclusion: The drug release profile was monitored over a period of 168 hours, and was free of burst effect before the protein coating. The results obtained from this work are promising; this work can be taken further to develop MTX based therapies.

  14. Synthesis of protein-coated biocompatible methotrexate-loaded PLA-PEG-PLA nanoparticles for breast cancer treatment

    Science.gov (United States)

    Massadeh, Salam; Alaamery, Manal; Al-Qatanani, Shatha; Alarifi, Saqer; Bawazeer, Shahad; Alyafee, Yusra

    2016-01-01

    Background PLA-PEG-PLA triblock polymer nanoparticles are promising tools for targeted dug delivery. The main aim in designing polymeric nanoparticles for drug delivery is achieving a controlled and targeted release of a specific drug at the therapeutically optimal rate and choosing a suitable preparation method to encapsulate the drug efficiently, which depends mainly on the nature of the drug (hydrophilic or hydrophobic). In this study, methotrexate (MTX)-loaded nanoparticles were prepared by the double emulsion method. Method Biodegradable polymer polyethylene glycol-polylactide acid tri-block was used with poly(vinyl alcohol) as emulsifier. The resulting methotrexate polymer nanoparticles were coated with bovine serum albumin in order to improve their biocompatibility. This study focused on particle size distribution, zeta potential, encapsulation efficiency, loading capacity, and in vitro drug release at various concentrations of PVA (0.5%, 1%, 2%, and 3%). Results Reduced particle size of methotrexate-loaded nanoparticles was obtained using lower PVA concentrations. Enhanced encapsulation efficiency and loading capacity was obtained using 1% PVA. FT-IR characterization was conducted for the void polymer nanoparticles and for drug-loaded nanoparticles with methotrexate, and the protein-coated nanoparticles in solid state showed the structure of the plain PEG-PLA and the drug-loaded nanoparticles with methotrexate. The methotrexate-loaded PLA-PEG-PLA nanoparticles have been studied in vitro; the drug release, drug loading, and yield are reported. Conclusion The drug release profile was monitored over a period of 168 hours, and was free of burst effect before the protein coating. The results obtained from this work are promising; this work can be taken further to develop MTX based therapies.

  15. Unusual case of left atrial myxoma with gastroesophageal junction adenocarcinoma.

    Science.gov (United States)

    Singh, Narinder Pal; Nagpal, Swapan Deep Singh; Goel, Arun Kumar; Dhingra, Bhupendra Kr

    2018-02-01

    Cardiac myxomas are rare tumors. Esophageal adenocarcinomas are common tumors of the gastrointestinal tract. Simultaneous occurrence of these tumors has not been reported. A 52-year-old gentleman presented to our hospital with dysphagia and was diagnosed with esophageal adenocarcinoma. Routine echocardiography discovered a cardiac tumor in the left atrium. The cardiac tumor was surgically removed and biopsy confirmed a myxoma. We removed the cardiac tumor as the first step and then initiated neoadjuvant chemotherapy. It is ideal to constitute a multidisciplinary team to decide on the course of treatment in such cases.

  16. Assessment of left atrial volume and function in patients with permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Agner, Bue F Ross; Kühl, Jørgen Tobias; Linde, Jesper James

    2014-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with substantial morbidity and mortality. AF is associated with enlargement of the left atrium (LA), and the LA volume has important prognostic implications for the disease. The objective of the study was to determine how...... measurements of LA volume and function obtained by transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR), and 320-slice multi-detector computed tomography (MDCT) correlate in patients with permanent AF....

  17. Left atrial leiomyosarcoma as cause of heart failure; Leiomiosarcoma atrial izquierdo como causa de insuficiencia cardiaca

    Energy Technology Data Exchange (ETDEWEB)

    Valdes Martin, Alexander [Instituto de Cardiologia y Cirugia Cardiovascular, La Habana (Cuba)

    2012-07-01

    The case of a 26 year-old patient with diagnosis of heart failure and presence of a mobile echogenic mass without calcification attached to the posterolateral area of the left atrium was reported. She underwent surgery and tissue examination evidenced a high-grade heart leiomyosarcoma. Postoperative course was satisfactory and her clinical state was rigorously monitored by oncology and heart specialists in the institution.

  18. Pacing Lead-Induced Granuloma in the Atrium: A Foreign Body Reaction to Polyurethane

    Directory of Open Access Journals (Sweden)

    Shinagawa Yoko

    2013-01-01

    Full Text Available We described a case of an 82-year-old male who presented with a granuloma entrapping the polyurethane-coated pacing lead at the site of contact on the atrium. He had been paced for 8 years without symptoms or signs suggestive of an allergic reaction to the pacemaker system and died from thrombosis of the superior mesenteric artery and heart failure. A histological examination of the nodule showed an incidental granuloma with multinucleated giant cells. No granuloma was found in the heart or the lung.

  19. Percutaneous retrieval of a vena cava filter from the right atrium: case report

    International Nuclear Information System (INIS)

    Rasuli, P.; Mehran, R.; French, G.; Turek, M.; Lalonde, K.A.; Cardinal, P.

    2000-01-01

    Migration of vena cava filters can occur spontaneously, but it can also occur as a result of entanglement of the filter with a guidewire, particularly during 'blind' (unguided) insertion of a central venous line. When a filter migrates to the heart, traditional practice has been either to leave the filter in place or to remove it surgically by means of open heart surgery and cardiopulmonary bypass. We found only 6 reports of successful percutaneous retrieval or repositioning of a vena cava filter (Table 1). We describe a new interventional technique for retrieving a filter from the right atrium and a novel endosurgical method for removing a filter from the innominate vein. (author)

  20. Extension of adrenocortical carcinoma into the right atrium – echocardiographic diagnosis: A case report

    Directory of Open Access Journals (Sweden)

    Rozenman Yoseph

    2003-05-01

    Full Text Available Abstract Background Adrenocortical carcinoma is a rare, highly malignant tumor. Cardiac involvement of the tumor is very rare. Echocardiography facilitates the evaluation of the cardiac involvement of the tumor. Case Presentation We describe a patient with an adrenal tumor. Transthoracic echo showed its extension into the right atrium. Accordingly, a combined abdominal and cardiac operation was performed, monitored by transesophageal echocardiography. Conclusion This case highlights the importance of echocardiography in revealing the cardiac involvement by this tumor and in planning the operative procedure.

  1. Early changes in left atrial volume after acute myocardial infarction

    DEFF Research Database (Denmark)

    Bakkestrom, R.; Andersen, Mads J; Ersboll, M.

    2016-01-01

    . The objective was to assess changes in LA volume early after MI in patients with diastolic dysfunction and the relation to invasive hemodynamics and natriuretic peptides. Methods: 62 patients with left ventricle ejection fraction (LVEF) >= 45%, diastolic E/e' > 8 and LA volume index >34 ml/m(2) within 48 h......Background: Dilatation of left atrium (LA) reflects chronic LA pressure or volume overload that possesses considerable prognostic information. Little is known regarding the interaction between LA remodeling after acute myocardial infarction (MI) and left atrial pressure at rest and during exercise...... of MI were enrolled. After 1 and 4 months blood sampling, echocardiography and right heart catheterization were performed during exercise test. Results: LA remodeling was considered in patients with a change from mild (35-41 ml/m(2)), to severe (>48ml/m(2)) dilatation after 4 months (Found in 22...

  2. Influence of the development organoclay bionanocomposites of PLA

    International Nuclear Information System (INIS)

    Cavalcanti, S.N.; Melo, T.J.A. de; Araujo, E.M.; Oliveira, A.D.B. de; Brito, G. de F.

    2011-01-01

    Until recently, it became important to develop more durable plastics to meet market needs, which have wide range of applications. But these materials which are derived from non-renewable source cause environmental impact due to the large amount of residue they produce. The aim of this paper is to present the production process of bionanocomposites using organoclay treated with the ionic surfactant Praepagen WB® in the polymer matrix of biodegradable PLA - Poly (lactic acid), to obtain the best properties and expand its applications. The techniques of X-ray diffraction, infrared spectroscopy (FTIR) showed that the organophilization process was efficient. The mechanical properties were modified, and impact strength showed considerable gain when the PLA was blended with a copolymer and organoclay. (author)

  3. Comparison of biatrial and left atrial radiofrequency ablation in patients with heart valves diseases

    Directory of Open Access Journals (Sweden)

    А. В. Богачев-прокофьев

    2015-10-01

    Full Text Available We analysed results of left atrial and biatrial anatomic scheme of radiofrequency (RF ablation of the atria in patients with valvular heart. From 2007 to 2011, RF ablation procedure performed 283 patients with atrial fibrillation and heart valve disease. Patients were divided into two groups - group I performed a complete circuit biatrial procedure (procedure maze IV - 131 patients, in group II only ablation of the left atrium -152 patients. Most of the patients had long-term persistent AF. The main problem of early postoperative period is dysfunction of pacemaker complex, which observed in 64.9% and 50.7% patients for group I and II, respectively (p = 0.031. Permanent dysfunction of pacemaker complex required implantation of permanent pacemaker (9.2% and 4.6% of cases for group I and II, respectively, p = 0,023. Predictors of dysfunction of the pacemaker complex were biatrial execution method and duration of AF. Freedom from AF and AT during 36 months after surgery was 80.4% for patients in group I and 78.5% for patients in group II, with no statistically significant difference (log-rank test, p = 0.621. Atrial transport function has not revealed that the active fraction of the right atrium was 29.8% higher than in group II in the early postoperative phase and by 17.9% in the long term, with no difference between groups for the left atrium has been received.

  4. Beyond the Strait: PLA Missions Other Than Taiwan

    Science.gov (United States)

    2009-04-01

    PLA Logistics and Command College, “China’s Peaceful Development and the PLA’s Historical Mission,” Junshi Jingji Yanjiu (Military Economics...Chubanshe, 2005, pp. 117-126, 163-172; Zhu Tingzhang, Zhongguo Zhoubian Anquan Huanjing yu Zhanlue (China’s Peripheral Security Environment and...on the Construction of Gas Pipelines in Central Asia”), Guoji Shiyou Jingji (International Petroleum Economics), Vol. 16, No. 2, 2008, www.cnki.net

  5. Processing-structure-properties relationships in PLA nanocomposite films

    Science.gov (United States)

    Di Maio, L.; Scarfato, P.; Garofalo, E.; Galdi, M. R.; D'Arienzo, L.; Incarnato, L.

    2014-05-01

    This work deals on the possibility to improve performances of PLA-based nanocomposite films, for packaging applications, through conveniently tuning materials and processing conditions in melt compounding technology. In particular, two types of polylactic acid and different types of filler selected from montmorillonites and bentonites families were used to prepare the hybrid systems by using a twin-screw extruder. The effect of biaxial drawing on morphology and properties of the nanocomposites, produced by film blowing, was investigated.

  6. Characteristics and cytotoxicity of folate-modified curcumin-loaded PLA-PEG micellar nano systems with various PLA:PEG ratios.

    Science.gov (United States)

    Phan, Quoc Thong; Le, Mai Huong; Le, Thi Thu Huong; Tran, Thi Hong Ha; Xuan, Phuc Nguyen; Ha, Phuong Thu

    2016-06-30

    Targeting delivery system use natural drugs for tumor cells is an appealing platform help to reduce the side effects and enhance the therapeutic effects of the drug. In this study, we synthesized curcumin (Cur) loaded (D, L Poly lactic - Poly ethylenglycol) micelle (Cur/PLA-PEG) with the ratio of PLA/PEG of 3:1 2:1 1:1 1:2 and 1:3 (w/w) and another micelle modified by folate (Cur/PLA-PEG-Fol) for targeting cancer therapy. The PLA-PEG copolymer was synthesized by ring opening polymerization method. After loading onto the micelle, solubility of Cur increased from 0.38 to 0.73mgml(-1). The average size of prepared Cur/PLA-PEG micelles was from 60 to 69nm (corresponding to the ratio difference of PLA/PEG) and the drug encapsulating efficiency was from 48.8 to 91.3%. Compared with the Cur/PLA-PEG micelles, the size of Cur/PLA-PEG-Fol micelles were from 80 to 86nm and showed better in vitro cellular uptake and cytotoxicity towards HepG2 cells. The cytotoxicity of the NPs however depends much on the PEG component. The results demonstrated that Folate-modified micelles could serve as a potential nano carrier to improve solubility, anti-cancer activity of Cur and targeting ability of the system. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Left atrial isolation associated with mitral valve operations.

    Science.gov (United States)

    Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

    1992-12-01

    Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent mitral valve operations. From May 1989 to September 1991, 62 patients underwent mitral valve operations (group I); 19, mitral valve operations and DeVega tricuspid annuloplasty (group II); 15, mitral and aortic operations (group III); and 4, mitral and aortic operations and DeVega tricuspid annuloplasty (group IV). Left atrial isolation was performed, prolonging the usual left paraseptal atriotomy toward the left fibrous trigone anteriorly and the posteromedial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesions were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 patients (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (group I, 80.7%; group II, 68.5%; group III, 86.7%; group IV, 75%; p = not significant). Three late deaths (3.1%) were registered. Long-term results show persistence of sinus rhythm in 71% of group I, 61.2% of group II, 85.8% of group III, and 100% of group IV. The unique risk factor for late recurrence of atrial fibrillation was found to be preoperative atrial fibrillation longer than 6 months. Due to the satisfactory success rate in recovering sinus rhythm, we suggest performing left atrial isolation in patients with chronic atrial fibrillation undergoing valvular operations.

  8. On the Use of PLA-PHB Blends for Sustainable Food Packaging Applications.

    Science.gov (United States)

    Arrieta, Marina Patricia; Samper, María Dolores; Aldas, Miguel; López, Juan

    2017-08-29

    Poly(lactic acid) (PLA) is the most used biopolymer for food packaging applications. Several strategies have been made to improve PLA properties for extending its applications in the packaging field. Melt blending approaches are gaining considerable interest since they are easy, cost-effective and readily available processing technologies at the industrial level. With a similar melting temperature and high crystallinity, poly(hydroxybutyrate) (PHB) represents a good candidate to blend with PLA. The ability of PHB to act as a nucleating agent for PLA improves its mechanical resistance and barrier performance. With the dual objective to improve PLAPHB processing performance and to obtain stretchable materials, plasticizers are frequently added. Current trends to enhance PLA-PHB miscibility are focused on the development of composite and nanocomposites. PLA-PHB blends are also interesting for the controlled release of active compounds in the development of active packaging systems. This review explains the most relevant processing aspects of PLA-PHB based blends such as the influence of polymers molecular weight, the PLA-PHB composition as well as the thermal stability. It also summarizes the recent developments in PLA-PHB formulations with an emphasis on their performance with interest in the sustainable food packaging field. PLA-PHB blends shows highly promising perspectives for the replacement of traditional petrochemical based polymers currently used for food packaging.

  9. Bilateral PLA/alginate membranes for the prevention of postsurgical adhesions.

    Science.gov (United States)

    Kessler, Martina; Esser, Eva; Groll, Jürgen; Tessmar, Jörg

    2016-11-01

    A bilateral barrier membrane for the prevention of postsurgical adhesions was developed. Thereby, a smooth PLA side was supposed to keep the affected tissues glidingly separated, while a mucoadhesive side made of alginate was meant to keep the barrier resident on the site of injury so that suturing becomes redundant or at least the membrane stays long enough to facilitate surgical handling. Because hydrophilic alginate and lipophilic PLA films show only low cohesion, solution electrospun meshes of PLA and PLA-PEG-PLA triblock copolymers with varying poly(ethylene glycol) [PEG] content were investigated as cohesion promoter to avoid an easy separation of the functionally different layers. Using direct electrospinning onto the PLA film, a modified contact surface of the mesh was created, which allowed the tested alginate solutions (3%, 5%) to infiltrate to different extents. Thereby, an increasing content of hydrophilic PEG within the mesh copolymer and a lower alginate concentration facilitated the infiltration. As a result, the PLA film with a PLA35k-PEG10k-PLA35k (racemic PLA chains) mesh and an alginate layer cast from a 3% alginate solution appeared to be the most effective combination as examined by means of a t peel test, a mucoadhesion test, a tensile test and optical evaluations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1563-1570, 2016. © 2015 Wiley Periodicals, Inc.

  10. Giant tumor thrombus in the right atrium clearly detected by /sup 111/In-oxine labeled platelet scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, T; Ishikawa, N; Satoh, A; Masuda, Y; Hiramatsu, Y; Akisada, M; Sakakibara, Y

    1985-07-01

    A 54-year-old man was admitted to hospital with a 3-month history of progressive dyspnea with coughing. A giant right atrial mass, originating from a hepatocellular carcinoma, was visualized by computed tomography, and digital subtraction angiography. The volume if the right atrial mass was increasing rapidly. It was therefore essential to determine whether this giant mass was a tumor thrombus or a multiplication of the hepatocellular carcinoma. /sup 111/In-oxine labeled platelet scintigraphy revealed active accumulation in the right atrium caused by the presence of active platelet deposition, and slight accumulation in the lung fields probably due to embolic showers originating from the tumor thrombus in the right atrium. This is the first case report showing that /sup 111/In-oxine labeled platelet scintigraphy can aid in confirming the nature of a giant tumor thrombus in the right atrium and can clarify the pathogenesis of the respiratory symptoms.

  11. Computer Simulation Investigation on the Effect of Channelled and Unchannelled Screens on Smoke Contamination in Atriums Upper Balconies

    Directory of Open Access Journals (Sweden)

    Nasif Mohammad Shakir

    2014-07-01

    Full Text Available This paper performed the effect of installing channel screen on smoke contamination in the presence of 0.5 m deep down stand in a fire compartment. The results are then compared with smoke contamination occurrence when the channel screens were removed. The results showed that there will be 96% increase in upper balconies smoke contamination in an atrium when no channel screens at fire compartment opening are used. This work provides new correlation obtained from numerical study which can predict the smoke contamination height in upper balconies of the atrium in the presence of 0.5 m down stand and no channel screens. The proposed correlation will be useful design tool for building designer to design safe shopping malls (atrium.

  12. Studies on PLA grafting onto graphene oxide and its effect on the ensuing composite films

    Energy Technology Data Exchange (ETDEWEB)

    Campos, João M., E-mail: jmdcampos@ua.pt [CICECO - Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Instituto de Biotecnologia e Bioengenharia (IBB) and Department of Chemical Engineering, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Ferraria, Ana M.; Botelho do Rego, Ana M. [Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Ribeiro, M. Rosário [Centro de Química Estrutural (CQE) and Department of Chemical Engineering, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Barros-Timmons, Ana [CICECO - Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal)

    2015-09-15

    Polylactide (PLA) with a terminal triple bond was synthesized by organocatalyzed ring-opening polymerization and coupled with azide-functionalized graphene oxide (GO) through an azide-alkyne cycloaddition “click” reaction. The functionalized graphenic species involved were analyzed by spectroscopic techniques (FT-IR, solid state {sup 13}C NMR, Raman), which confirmed the coupling of PLA and GO. Additionally, an in depth study of the prepared GO, intermediates and GO-g-PLA hybrid was carried out that sheds light on the mechanisms involved in the functionalization path. The obtained GO-g-PLA hybrid, containing at least 20% of biopolymer, presented an exfoliated graphenic structure, as established by XRD. The conditions used in the grafting of the PLA chains inhibited the crystallization and melting observed for the free polymer. Furthermore, the graphene oxide seems to be reduced during functionalization, which can also be an advantage. Nanocomposites were obtained as solvent-cast films, prepared by dispersion of the GO-g-PLA hybrid in commercial PLA. Preliminary results regarding the performance of these nanocomposites, obtained by DSC and DMA, highlighted the effect of functionalization. Loading values as low as 0.5% suffice to improve the mechanical properties over a broad temperature range due to the high surface area resulting from the good dispersibility of polymer functionalized nanofillers and/or their effect on the polymer chain organization. - Highlights: • A graphene oxide/PLA (GO-g-PLA) hybrid was obtained by a grafting-to method. • Grafting of PLA chains onto the surface of GO inhibited polymer crystallization. • The GO-g-PLA material was used in the reinforcement of PLA, as nanocomposite films. • GO-g-PLA provides more homogeneously reinforced nanocomposite films, than neat GO. • Nanocomposite films with 0.5% loading present high storage modulus even above T{sub g}.

  13. Reinforcement of a porous collagen scaffold with surface-activated PLA fibers.

    Science.gov (United States)

    Liu, Xi; Huang, Changbin; Feng, Yujie; Liang, Jie; Fan, Yujiang; Gu, Zhongwei; Zhang, Xingdong

    2010-01-01

    A hybrid porous collagen scaffold mechanically reinforced with surface-activated poly(lactic acid) (PLA) fiber was prepared. PLA fibers, 20 mum in diameter and 1 mm in length, were aminolyzed with hexanediamine to introduce free amino groups on the surfaces. After the amino groups were transferred to aldehyde groups by treatment with glutaraldehyde, different amounts (1.5, 3, 5 and 8 mg) of surface-activated PLA fibers were homogeneously mixed with 2 ml type-I collagen solution (pH 2.8, 0.6 wt%). This mixture solution was then freeze-dried and cross-linked to obtain collagen sponges with surface-activated PLA fiber. Scanning electron microscopy observation indicated that the collagen sponges had a highly interconnected porous structure with an average pore size of 170 mum, irrespective of PLA fiber incorporation. The dispersion of surface-activated PLA fibers was homogeneous in collagen sponge, in contrast to unactivated PLA fibers. The compression modulus test results showed that, compared with unactivated PLA fibers, the surface-activated PLA fibers enhanced the resistance of collagen sponge to compression more significantly. Cytotoxicity assay by MTT test showed no cytotoxicity of these collagen sponges. L929 mouse fibroblast cell-culture studies in vitro revealed that the number of L929 cells attached to the collagen sponge with surface-activated PLA fibers, both 6 h and 24 h after seeding, was higher than that in pure collagen sponge and sponge with unactivated PLA fibers. In addition, a better distribution of cells infiltrated in collagen sponge with surface-activated PLA fibers was observed by histological staining. These results indicated that the collagen sponge reinforced with surface-activated PLA fibers is a promising biocompatible scaffold for tissue engineering.

  14. Studies on PLA grafting onto graphene oxide and its effect on the ensuing composite films

    International Nuclear Information System (INIS)

    Campos, João M.; Ferraria, Ana M.; Botelho do Rego, Ana M.; Ribeiro, M. Rosário; Barros-Timmons, Ana

    2015-01-01

    Polylactide (PLA) with a terminal triple bond was synthesized by organocatalyzed ring-opening polymerization and coupled with azide-functionalized graphene oxide (GO) through an azide-alkyne cycloaddition “click” reaction. The functionalized graphenic species involved were analyzed by spectroscopic techniques (FT-IR, solid state "1"3C NMR, Raman), which confirmed the coupling of PLA and GO. Additionally, an in depth study of the prepared GO, intermediates and GO-g-PLA hybrid was carried out that sheds light on the mechanisms involved in the functionalization path. The obtained GO-g-PLA hybrid, containing at least 20% of biopolymer, presented an exfoliated graphenic structure, as established by XRD. The conditions used in the grafting of the PLA chains inhibited the crystallization and melting observed for the free polymer. Furthermore, the graphene oxide seems to be reduced during functionalization, which can also be an advantage. Nanocomposites were obtained as solvent-cast films, prepared by dispersion of the GO-g-PLA hybrid in commercial PLA. Preliminary results regarding the performance of these nanocomposites, obtained by DSC and DMA, highlighted the effect of functionalization. Loading values as low as 0.5% suffice to improve the mechanical properties over a broad temperature range due to the high surface area resulting from the good dispersibility of polymer functionalized nanofillers and/or their effect on the polymer chain organization. - Highlights: • A graphene oxide/PLA (GO-g-PLA) hybrid was obtained by a grafting-to method. • Grafting of PLA chains onto the surface of GO inhibited polymer crystallization. • The GO-g-PLA material was used in the reinforcement of PLA, as nanocomposite films. • GO-g-PLA provides more homogeneously reinforced nanocomposite films, than neat GO. • Nanocomposite films with 0.5% loading present high storage modulus even above T_g.

  15. Electrospun PBLG/PLA nanofiber membrane for constructing in vitro 3D model of melanoma.

    Science.gov (United States)

    Wang, Yaping; Qian, Junmin; Liu, Ting; Xu, Weijun; Zhao, Na; Suo, Aili

    2017-07-01

    Though much progress in utilizing tissue engineering technology to investigate tumor development in vitro has been made, the effective management of human melanoma is still a challenge in clinic due to lack of suitable 3D culture systems. In this study, we prepared a poly(γ-benzyl-l-glutamate)/poly(lactic acid) (PBLG/PLA) nanofiber membrane by electrospinning and demonstrated its suitability as a matrix for 3D culture of melanoma cells in vitro. The electrospun PBLG/PLA nanofiber membrane displayed a smooth and uniform fibrous morphology and had a desirable water contact angle of 79.3±0.6°. The average diameter of PBLG/PLA nanofibers was 320.3±95.1nm that was less than that (516.2±163.3nm) of pure PLA nanofibers. The addition of PBLG into PLA decreased the cold crystallization peak of PLA fibers from 93 to 75°C. The in vitro biocompatibility of PBLG/PLA nanofiber membrane was evaluated with B16F10 cells using PLA nanofiber membrane as control. It was found that, compared to PLA nanofiber membrane, PBLG/PLA nanofiber membrane could better support cell viability and proliferation, as indicated by MTT assay and live-dead staining. SEM results revealed that PBLG/PLA rather than PLA nanofiber membrane promoted the generation of tumoroid-like structures. These findings clearly demonstrated that the electrospun PBLG/PLA nanofiber membrane could mimick the extracellular matrix of melanoma microenvironment and be a promising platform for 3D cell culture. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. EFFECTS OF AEROBIC TRAINING ON THE CARDIOMYOCYTES OF THE RIGHT ATRIUM OF MICE

    Directory of Open Access Journals (Sweden)

    Vanessa Gonçalves Coutinho de Oliveira

    Full Text Available ABSTRACT Introduction: Polypeptide hormones (natriuretic peptides, NPs are secreted by the cardiac atria and play an important role in the regulation of blood pressure. Objective: To evaluate the effects of aerobic training on the secretory apparatus of NPs in cardiomyocytes of the right atrium. Methods: Nine-month-old mice were divided in two groups (n=10: control group (CG and trained group (TG. The training protocol was performed on a motor treadmill for 8 weeks. Systolic blood pressure was measured at the beginning of the experiment (9 months of age and at moment of the sacrifice (11 months of age. Electron micrographs were used to quantify the following variables: the quantitative density and area of NP granules, the relative volumes of the mitochondria, endoplasmic reticulum, and Golgi complex and the relative volume of euchromatin in the nucleus and the number of pores per 10 µm of the nuclear membrane. The results were compared by Student's t test (p< 0.05. Results: The cardiomyocytes obtained from TG mice showed increased density and sectional area of secretory granules of NP, higher relative volume of endoplasmic reticulum, mitochondria, and Golgi complex compared with the CG mice. Furthermore, the quantitative density of nuclear pores and the relative volume of euchromatin in the nucleus were significantly higher compared with the CG mice. Conclusion: Aerobic training caused hypertrophy of the secretory apparatus in the cardiomyocytes of right atrium, which could explain the intense synthesis of natriuretic peptides in trained mice with respect to the untrained mice.

  17. Case of right atrial myxoma with right to left shunt

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Kenji; Suzuki, Tomoyuki; Ohzeki, Tetsuro (Iwate Medical Coll., Morioka (Japan). School of Medicine)

    1982-12-01

    A case of 49-year-old woman with right atrial myxoma resulting to right to left shunt, diagnosed by cardiac pool isotope image, was reported. She was admitted to our clinic because of progressive shortness of breath. At admission lip cyanosis was noted. Laboratory data included polycythemia, low O/sub 2/ saturation (89%) and high erythrocyte sedimentation rate (65 mm/1 h). Chest x-p showed slight right atrial enlargement, but no pulmonary congestion. The electrocardiogram showed sinus regular rhythm with biphasic p wave in leads II, III, aVf. Although 1st heart sound at the apex was splited, no heart murmur was heard. In usual echocardiographic approach, no abnormal echogram was obtained in the right ventricular region. Lung perfusion scintiscan with Tc-99 m-MAA showed visualization of thyroid gland and kidney, which suggested intracardiac right-to-left shunt. Cardiac pool image with Tc-99m-HSA revealed large photo-deficient area in the right atrium and early visualization of aortic arch. Computor tomography showed large round low density region 8 x 7 cm in size. Based on their findings, this patient was diagnosed as right atrial tumor. At operation a large tumor (diameter 8 x 7 x 7 cm, weight 160g) filled the lower part of the right atrium and was adherent to the anterolateral wall in the right atrium. As a cause of R-L shunt, streched foramen ovale (5 x 10 mm) was found. Tumor histology was typical of atrial myxoma. Post-operative gated cardiac isotope image showed no evidence of residual atrial tumor. Cardiac blood pool isotope imaging was a method for the noninvasive detection and assessment of right atrial myxoma.

  18. Multi-functional biomimetic surfaces of PLA based biomaterials created by printing of functional PLA-b-PEO colloids

    Czech Academy of Sciences Publication Activity Database

    Mázl Chánová, Eliška; Knotek, P.; Yang, Y.; Zárubová, Jana; Machová, Luďka; Janoušková, Olga; Proks, Vladimír; Kučka, Jan; Bačáková, Lucie; Rypáček, František; Kubies, Dana

    2016-01-01

    Roč. 7, 2 (Suppl) (2016), s. 74 ISSN 2157-7552. [International Conference on Tissue Engineering & Regenerative Medicine /5./. 12.09.2016-14.09.2016, Berlin] R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 ; RVO:67985823 Keywords : biomimetic surfaces * RGD * PLA-b-PEO copolymer Subject RIV: EB - Genetics ; Molecular Biology; EI - Biotechnology ; Bionics (FGU-C)

  19. Numerical investigation on the effect of balcony open and solid upstand on smoke contamination in atrium balconies

    Science.gov (United States)

    Mutafi, M. A.; Nasif, M. S.; Pao, W.; Ismail, F. B.

    2017-10-01

    Atrium is a modern architectural design of buildings that has an open space at the middle and contains several floors. In atrium structure the smoke due to fire can easily flow through the open spaces and causes smoke contamination. CFD simulation using fire dynamic simulator (FDS) software is conducted in this work, to investigate the effect of balcony open upstand on smoke contamination in atrium’s balconies and compare it with balconies with solid upstand. It was found that in case of open upstand, the smoke contamination occurrence decreased inside the balcony comparing with balconies with solid upstand.

  20. [Localization of substance P- and FMRFamide-like immunoreactivity in the atrium of the snail Achatina fulica].

    Science.gov (United States)

    Shabel'nikov, S V; Bystrova, O A; Martynova, M G

    2008-01-01

    By immunohistochemical and immunocytochemical methods localization of Substanse P (SP) and FMRFamide in the atrium of the snail Achatina fulica was investigated. Nerve fibers innervating the snail atrium contact tightly with the granular cells (GC) situated between muscle and endocardial cells, forming neuroendocrine units. Both neuromediators were found in the cells of the neuroendocrine units. By immunohistochemistry SP- and FMRFamide-immunoreactive material was revealed in the granules of the atrial GC. Elecrtonmicroscopical immunocytochemistry has confirmed the presence of SP- and FMRFamide-immunoreactive material in the granules of the GC and shown their presence in the neurosecretory granules of the nerve endings contacting both the atrial GC and cardiomyocytes.

  1. Crosslinked bicontinuous biobased PLA/NR blends via dynamic vulcanization using different curing systems.

    Science.gov (United States)

    Yuan, Daosheng; Chen, Kunling; Xu, Chuanhui; Chen, Zhonghua; Chen, Yukun

    2014-11-26

    In this study, blends of entirely biosourced polymers, namely polylactide (PLA) and natural rubber (NR), were prepared through dynamic vulcanization using dicumyl peroxide (DCP), sulphur (S) and phenolic resin (2402) as curing agents, respectively. The crosslinked NR phase was found to be a continuous structure in all the prepared blends. The molecular weight changes of PLA were studied by gel permeation chromatography. Interfacial compatibilization between PLA and NR was investigated using Fourier transform infrared spectroscopy and scanning electron microscopy. The thermal properties of blends were evaluated by differential scanning calorimetry and thermogravimetric analysis instrument. It was found that the molecular weight of PLA and interfacial compatibilizaion between PLA and NR showed a significant influence on the mechanical and thermal properties of blends. The PLA/NR blend (60/40 w/w) by DCP-induced dynamic vulcanization owned the finest mechanical properties and thermal stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Morphology of Poly lactide/Polycaprolactone (PLA/PCL) Nano composite by Scanning Electron Microscopy (SEM)

    International Nuclear Information System (INIS)

    Siti Zulaiha Hairaldin; Wan Md Zin Wan Yunus; Norazowa Ibrahim

    2011-01-01

    In this study, Octadecylamine Modified Montmorillonites (ODAMMT) were used to prepare Poly lactide/ Polycaprolactone (PLA/ PCL) nano composites. PLA and PCL mix in 90:10 ratios, using an internal mixer by melt blending technique. The other sample was blend with Natrium Montmorillonite (NaMMT) and Octadecylamine Modified Montmorillonite (ODA-MMT) to produce PLA/ PCL-NaMMT and PLA/ PCL ODAMMT. To characterize the polymer nano composites, X-ray diffraction (XRD), FTIR and SEM analysis were conducted. Comparison of morphology were made up between PLA/ PCL, PLA/ PCL with presence of 7 % of Na-MMT and 7 % ODA-MMT respectively based on SEM micrograph by calculate the number-average diameter. (author)

  3. Effect of the state of water and relative humidity on ageing of PLA films.

    Science.gov (United States)

    Rocca-Smith, J R; Chau, N; Champion, D; Brachais, C-H; Marcuzzo, E; Sensidoni, A; Piasente, F; Karbowiak, T; Debeaufort, F

    2017-12-01

    Various types of food are now commercialized in packaging materials based on poly(lactic acid) (PLA) due to its eco-friendly nature. However, one of the main limitations related to PLA is its reactivity with water. For food applications, it is of critical importance to better understand the hydrolysis of PLA driven by water molecules either in liquid or in vapour state. This work focuses on the modifications of PLA induced by water when simulating contact with semi-dry foods (a w ≈0.5), high moisture foods (a w ≈1) and liquid foods (a w ≈1). This study undoubtedly shows that both the chemical potential of water and its physical state influence the hydrolytic degradation of PLA films. From a practical point of view, PLA packaging is very well suited for semi-dry foods, but is highly sensitive to high moisture and liquid foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations.

    Science.gov (United States)

    Scaffaro, Roberto; Lopresti, Francesco; Sutera, Alberto; Botta, Luigi; Fontana, Rosa Maria; Gallo, Giuseppe

    2017-09-01

    Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O 2 -plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-pigmented undecylprodigiosin (RED), and constitutes a model for the study of antibiotic-producing actinomycetes. Wet contact angles and X-ray photoelectron spectroscopy analysis confirmed the increased wettability of PLA-plasma due to the formation of polar functional groups such as carboxyl and hydroxyl moieties. Scanning electron microscope observations, carried out at different incubation times, revealed that S. coelicolor immobilized-cells created a dense "biofilm-like" mycelial network on both kinds of PLA membranes. Cultures of S. coelicolor immobilized-cells on PLA or PLA-plasma membranes produced higher biomass (between 1.5 and 2 fold) as well as higher levels of RED and ACT than planktonic cultures. In particular, cultures of immobilized-cells on PLA and PLA-plasma produced comparable levels of RED that were approximatively 4 and 5 fold higher than those produced by planktonic cultures, respectively. In contrast, levels of ACT produced by immobilized-cell cultures on PLA and PLA-plasma were different, being 5 and 10 fold higher than those of planktonic cultures, respectively. Therefore, this is study demonstrated the positive influence of PLA membrane on growth and secondary metabolite production in S. coelicolor and also revealed that O 2 -plasma treated PLA membranes

  5. Visitors׳ perceptions on the important factors of atrium design in shopping centers: A study of Gandaria City Mall and Ciputra World in Indonesia

    Directory of Open Access Journals (Sweden)

    Astrid Kusumowidagdo

    2016-03-01

    The research was conducted with the sequential exploratory method, which involved a qualitative study, followed by a quantitative study. The objects of this research were two shopping centers located in the two largest cities in Indonesia, namely, Gandaria City Mall in Jakarta and Ciputra World in Surabaya. A total of 43 informants were a part of the qualitative data collection, and 350 respondents served as survey participants. The survey research shows that the design factors considered by visitors at the Gandaria City Mall are atrium legibility, atrium decoration, event decoration, social image and interaction, and event ambience, whereas the visitors at Ciputra World considered atrium legibility, social image and interaction, atrium ambience, and atrium decoration.

  6. Polymer Film-Based Screening and Isolation of Polylactic Acid (PLA)-Degrading Microorganisms.

    Science.gov (United States)

    Kim, Mi Yeon; Kim, Changman; Moon, Jungheun; Heo, Jinhee; Jung, Sokhee P; Kim, Jung Rae

    2017-02-28

    Polylactic acid (PLA) has been highlighted as an alternative renewable polymer for the replacement of petroleum-based plastic materials, and is considered to be biodegradable. On the other hand, the biodegradation of PLA by terminal degraders, such as microorganisms, requires a lengthy period in the natural environment, and its mechanism is not completely understood. PLA biodegradation studies have been conducted using mainly undefined mixed cultures, but only a few bacterial strains have been isolated and examined. For further characterization of PLA biodegradation, in this study, the PLA-degrading bacteria from digester sludge were isolated and identified using a polymer film-based screening method. The enrichment of sludge on PLA granules was conducted with the serial transference of a subculture into fresh media for 40 days, and the attached biofilm was inoculated on a PLA film on an agar plate. 3D optical microscopy showed that the isolates physically degraded the PLA film due to bacterial degradation. 16S rRNA gene sequencing identified the microbial colonies to be Pseudomonas sp. MYK1 and Bacillus sp. MYK2. The two isolates exhibited significantly higher specific gas production rates from PLA biodegradation compared with that of the initial sludge inoculum.

  7. A study on properties of PLA/PBAT from blown film process

    International Nuclear Information System (INIS)

    Hongdilokkul, P; Keeratipinit, K; Chawthai, S; Suttiruengwong, S; Hararak, B; Seadan, M

    2015-01-01

    The aim of this work was to study the properties of films based on PLA/PBAT blend prepared by the reactive compounding. PLA/PBAT blends were prepared at the weight ratio of 80:20 together with peroxide as a reactive agent in a twin screw extruder with temperature profile of 160/170/180/210/220/190/175/150°C from feed to die zone. All blended samples, neat PLA, and neat PBAT were characterized for morphology, mechanical and rheological properties. SEM micrographs showed finely dispersed phases of PBAT in PLA in all cases. The particle sizes of PBAT were around 1 μm. The results indicated that the drawability and toughness properties of PLA were greatly improved when blended with 20%wt PBAT. The interface adhesion, and mechanical properties of PLA/PBAT blends were also improved when adding a very small quantity of peroxide. PLA/PBAT blends were then used to produce films. The film characteristics and mechanical properties were examined. Tensile strength of films was significantly improved in the machine direction in PLA/PBAT/peroxide blends whereas the good optical transparent property were remained the same compared with neat PLA. (paper)

  8. Structure and blood compatibility of highly oriented PLA/MWNTs composites produced by solid hot drawing.

    Science.gov (United States)

    Li, Zhengqiu; Zhao, Xiaowen; Ye, Lin; Coates, Phil; Caton-Rose, Fin; Martyn, Michasel

    2014-03-01

    Highly oriented poly(lactic acid) (PLA)/multi-walled carbon nanotubes (MWNTs) composites were fabricated through solid hot drawing technology in an effort to improve the mechanical properties and blood biocompatibility of PLA as blood-contacting medical devices. It was found that proper MWNTs content and drawing orientation can improve the tensile strength and modulus of PLA dramatically. With the increase in draw ratio, the cold crystallization peak became smaller, and the glass transition and the melting peak of PLA moved to high temperature, while the crystallinity increased, and the grain size decreased, indicating the stress-induced crystallization of PLA during drawing. MWNTs showed a nucleation effect on PLA, leading to the rise in the melting temperature, increase in crystallinity and reduction of spherulite size for the composites. Moreover, the intensity of (002) diffraction of MWNTs increased with draw ratio, indicating that MWNTs were preferentially aligned and oriented during drawing. Microstructure observation demonstrated that PLA matrix had an ordered fibrillar bundle structure, and MWNTs in the composite tended to align parallel to the drawing direction. In addition, the dispersion of MWNTs in PLA was also improved by orientation. Introduction of MWNTs and drawing orientation could significantly enhance the blood compatibility of PLA by prolonging kinetic clotting time, reducing hemolysis ratio and platelet activation.

  9. Persistent left superior vena cava with absent right superior vena cava: image findings

    International Nuclear Information System (INIS)

    Araujo Junior, Cyrillo Rodrigues de; Carvalho, Tarcisio Nunes; Fraguas Filho, Sergio Roberto; Costa, Marlos Augusto Bitencourt; Jacob, Beatriz Mahmud; Machado, Marcio Martins; Teixeira, Kim-Ir-Sen Santos; Ximenes, Carlos Alberto

    2003-01-01

    Persistent left superior vena cava absent right superior vena cava is a rare anomaly, with less than 150 cases reported in the literature. Congenitally persistent left superior vena cava is the most common variant of systemic venous return to the heart, resulting embryologically from failure of the left anterior cardinal vein to become obliterated. Its incidence varies from 0.3% in patients with otherwise normal heart to 4.3% in patients with congenital heart disease. In the majority of the patients, a right superior vena cava is present as well, but rarely the right anterior cardinal vein degenerates resulting in the absence of the normal right superior vena cava. The blood from the right side is carried by the persistent left superior vena cava to the right atrium through the coronary sinus. We report the case of a patient with a persistent left superior vena cava and absence of right superior vena cava identified by chance during a chest radiograph and computed tomography examination for investigation of chronic pulmonary obstructive disease. The patient had no congenital heart disease and the blood from the right side was drained by the persistent left superior vena cava into the right atrium through the coronary sinus. (author)

  10. Investigation on Smoke Movement and Smoke Control for Atrium in Green and Sustainable Buildings

    DEFF Research Database (Denmark)

    Fang, Lui; Nielsen, Peter V.; Brohus, Henrik

    The concepts of green buildings and sustainable buildings are promoted actively in the developed countries. Targets are on protecting the environment, using less energy through natural ventilation provisions and daylight utilization, developing better waste management and taking resource...... design in the green or sustainable buildings with an atrium. Since the physics of air entrainment is not yet clearly understood, most of the fire plume expressions reported in the literature was derived empirically. Experiments and CFD simulation were used to study the different types of thermal plumes...... conservation into account. Architectural and building design, electrical and mechanical systems, and building management have to be upgraded. However, there are problems in dealing with fire safety, especially in complying with the existing prescriptive fire codes. A hot argument is that smoke control system...

  11. Percutaneous retrieval of a vena cava filter from the right atrium: case report

    Energy Technology Data Exchange (ETDEWEB)

    Rasuli, P. [The Ottawa Hospital and University of Ottawa, Dept. of Radiology, Ottawa, Ontario (Canada); Mehran, R. [The Ottawa Hospital and University of Ottawa, Dept. of Thoracic Surgery, Ottawa, Ontario (Canada); French, G. [The Ottawa Hospital and University of Ottawa, Dept. of Radiology, Ottawa, Ontario (Canada); Turek, M. [The Ottawa Hospital and University of Ottawa, Dept. of Internal Medicine, Ottawa, Ontario (Canada); Lalonde, K.A. [The Ottawa Hospital and University of Ottawa, Dept. of Thoracic Surgery, Ottawa, Ontario (Canada); Cardinal, P. [The Ottawa Hospital and University of Ottawa, Dept. of Internal Medicine, Ottawa, Ontario (Canada)

    2000-07-01

    Migration of vena cava filters can occur spontaneously, but it can also occur as a result of entanglement of the filter with a guidewire, particularly during 'blind' (unguided) insertion of a central venous line. When a filter migrates to the heart, traditional practice has been either to leave the filter in place or to remove it surgically by means of open heart surgery and cardiopulmonary bypass. We found only 6 reports of successful percutaneous retrieval or repositioning of a vena cava filter (Table 1). We describe a new interventional technique for retrieving a filter from the right atrium and a novel endosurgical method for removing a filter from the innominate vein. (author)

  12. Characterization Plan for Soils Around Drain Line PLA-100115

    Energy Technology Data Exchange (ETDEWEB)

    D. Shanklin

    2006-05-24

    This Characterization Plan supports the Hazardous Waste Management Act/Resource Conservation and Recovery Act (HWMA/RCRA) closure of soils that may have been contaminated by releases from drain line PLA-100115, located within the Idaho Nuclear Technology and Engineering Center at the Idaho National Laboratory Site. The requirements to address the closure of soils contaminated by a potential release from this line in a characterization plan was identified in the "HWMA/RCRA Less Than 90-day Generator Closure Report for the VES-SFE-126."

  13. Plant Atrium System for Food Production in NASA's Deep Space Habitat Tests

    Science.gov (United States)

    Massa, Gioia D.; Simpson, Morgan; Wheeler, Raymond M.; Newsham, Gerald; Stutte, Gary W.

    2013-01-01

    In preparation for future human exploration missions to space, NASA evaluates habitat concepts to assess integration issues, power requirements, crew operations, technology, and system performance. The concept of a Food Production System utilizes fresh foods, such as vegetables and small fruits, harvested on a continuous basis, to improve the crew's diet and quality of life. The system would need to fit conveniently into the habitat and not interfere with other components or operations. To test this concept, a plant growing "atrium" was designed to surround the lift between the lower and upper modules of the Deep Space Habitat and deployed at NASA Desert Research and Technology Studies (DRATS) test site in 2011 and at NASA Johnson Space Center in 2012. With this approach, no-utilized volume provided an area for vegetable growth. For the 2011 test, mizuna, lettuce, basil, radish and sweetpotato plants were grown in trays using commercially available red I blue LED light fixtures. Seedlings were transplanted into the atrium and cared for by the. crew. Plants were then harvested two weeks later following completion of the test. In 2012, mizuna, lettuce, and radish plants were grown similarly but under flat panel banks of white LEDs. In 2012, the crew went through plant harvesting, including sanitizing tlie leafy greens and radishes, which were then consumed. Each test demonstrated successful production of vegetables within a functional hab module. The round red I blue LEDs for the 2011 test lighting cast a purple light in the hab, and were less uniformly distributed over the plant trays. The white LED panels provided broad spectrum light with more uniform distribution. Post-test questionnaires showed that the crew enjoyed tending and consuming the plants and that the white LED light in 2012 provided welcome extra light for the main HAB AREA.

  14. Left atrial spindle cell sarcoma – Case report

    Directory of Open Access Journals (Sweden)

    Nihar Mehta

    2012-07-01

    Full Text Available Primary spindle cell sarcoma of the left atrium is an extremely rare tumour. Surgical excision is the mainstay of treatment since it responds poorly to chemotherapy or radiotherapy. In spite of all the treatment, the prognosis remains poor due to inadvertent delay in diagnosis, few therapeutic options and propensity to metastasize. We present a 47-year-old male who underwent a surgical excision of a left atrial mass in February 2010. It was proved to be a high-grade spindle cell sarcoma on histopathology. He presented again in October 2010 with recurrence of the tumour for which he was re-operated. However, the tumour recurred again within one month, to which the patient succumbed.

  15. Left atrial thrombus following bilobectomy: a case report

    Directory of Open Access Journals (Sweden)

    Kaya Ugur

    2010-02-01

    Full Text Available Abstract Introduction Left atrial free floating ball thrombus is a relatively rare event, especially without mitral valve disease. Case presentation A 61-year-old Turkish man was admitted to our hospital with a thrombus mass in his left atrium. Five months earlier, he had undergone right bilobectomy and superior bronchoplasty due to squamous cell carcinoma in the lung. The patient had no evidence of cardiac disease except atrial fibrillation and there were no defined embolizations. The thrombus mass was surgically removed. The patient was discharged from hospital on the sixth postoperative day. Conclusion Surgery with cardiopulmonary bypass is a safe method for treatment. The patient should be medicated with warfarin, especially in the presence of atrial fibrillation.

  16. Polymer blends of polylactic acid (PLA) and polybutylene succinate-adipate

    Science.gov (United States)

    Ma, Wenguang

    A series of blends consisting of polylactic acid (PLA) and aliphatic succinate polyester (BionolleRTM #3000) had been prepared and investigated. The results of mechanical property investigations showed that using 20 wt% Bionolle#3000 can significantly increase the toughness of PLA. BionolleRTM #3000 also reduces the physical aging rate of PLA so blends remain tough longer. Conversely, the stiffness of BionolleRTM #3000 can be significantly increased by blending in PLA. DMA and DSC results show that PLA/BionolleRTM 3000 blends are not thermodynamically miscible, but are compatible blends. Studies have also been performed to determine the amount and rate of aerobic biodegradation of PLA/aliphatic succinate polyester blends in biologically active composting, enzymatic, and soil environments. The changes in molecular weight, molecular structure and thermal properties in the composting environment were also studied by GPC, NMR and DSC analyses. The research results showed BionolleRTM #3000 had a high degradation rate, while PLA had a low degradation rate. PLA/BionolleRTM #3000 blends had moderate degradation rates that increased with BionolleRTM #3000 content. The melt flow behavior of PLA/BionolleRTM #3000 blends has been studied by capillary rheometry. The relationship of the blends' viscosity with their composition, shear stress, shear rate, and temperature has been investigated. Power law index and activation energy of PLA, BionolleRTM #3000 and their blends have been calculated. The experimental and theoretical data can let us understand the processability of PLA/BionolleRTM #3000 blends. A scanning electron microscope (SEM) was used to investigate the morphological structure of the PLA/BionolleRTM #3000 blends. Micrographs of the samples made from different methods (blown film, extrudate and compression molding sheet) were taken; their differences in morphology were compared. For comparison, the micrographs of blend PLA/BionolleRTM #6000 was also studied. The

  17. PLA/CS/Nifedipine Nanocomposite Films: Properties and the In Vitro Release of Nifedipine

    Science.gov (United States)

    Trang, Nguyen Thi Thu; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Thanh, Dinh Thi Mai; Lam, Tran Dai; Hoang, Thai

    2016-07-01

    The polylactic acid (PLA)/chitosan (CS) films containing a drug, nifedipine (NIF), in the presence of polyethylene oxide (PEO) as a compatibilizer were prepared by the solution method. This method has not been used to form films containing four components (PLA, CS, NIF, PEO) up to now. The CS, PEO, and NIF contents are 25 wt.%, 6-8 wt.%, and 10-50 wt.% in comparison with PLA weight, respectively. Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM) were used to characterize the interactions, properties, and morphology of the PLA/CS/PEO/NIF films. The FTIR, TGA, and DSC results show that NIF carried by PLA/CS/PEO films and PLA, CS, NIF had better interaction and were more compatible when using PEO. The surface morphology of PLA/CS/PEO/NIF films was similar to that of PLA/CS/PEO films. Moreover, this was the first time drug loading and NIF release content from PLA/CS/PEO films were determined by the ultraviolet-visible (UV-Vis) spectroscopy method. The drug loading of PLA/CS/PEO/NIF films was from 80.99% to 93.61%. The in vitro NIF release studies were carried out in pH 2, 6.8, and 7.4 solutions corresponding to the pH of stomach, colon, and duodenum regions in the human body, respectively. The NIF release content in different pH solutions is in the order: pH 2 > pH 6.8 > pH 7.4 and increases when there is increasing NIF loading. The PLA/CS/PEO films are potential materials to apply for long-circulating systems for NIF delivery.

  18. Preparation of flexible PLA/PEG-POSS nanocomposites by melt blending and radiation crosslinking

    International Nuclear Information System (INIS)

    Jung, Chang-Hee; Hwang, In-Tae; Jung, Chan-Hee; Choi, Jae-Hak

    2014-01-01

    In this study, poly(lactic acid) (PLA)/poly(ethylene glycol)-functionalized polyhedral oligomeric silsesquioxane (PEG-POSS) nanocomposites with or without triallyl isocyanurate (TAIC) were investigated by melt blending and electron beam irradiation to enhance the flexibility of PLA. Based on the results of the crosslinking degree measurements, the PLA/PEG-POSS nanocomposites were crosslinked by electron beam irradiation in the presence of triallyl isocyanurate (TAIC) and their crosslinking degree reached up to 80% based on the absorbed dose and their compositions. From the results of the FE-SEM and EDX Si-mapping, the crosslinked PLA/PEG-POSS nanocomposites were homogenous without a micro-phase separation or radiation-induced morphological change. Based on the results of the tensile test, the PLA/PEG-POSS nanocomposites containing 15 wt% PEG-POSS exhibited the highest flexibility, and their tensile strength showed a maximum value of 44.5 MPa after electron beam irradiation at an absorbed dose of 100 kGy in the presence of TAIC, which is comparable to non-biodegradable polypropylene. The results of the dynamic mechanical analysis revealed that the crosslinked PLA/PEG-POSS nanocomposites exhibited a higher thermal resistance above their melting temperature in comparison to that of the neat PLA, although their glass transition temperature was lower than that of the neat PLA. The enzymatic biodegradation test revealed that the PLA/PEG-POSS nanocomposites were biodegradable even though their biodegradability was deteriorated in comparison to that of the neat PLA. - Highlights: • PLA/PEG-POSS nanocomposites were prepared by melt blending. • The nanocomposites containing TAIC were crosslinked by electron beam irradiation. • The mechanical properties of the nanocomposites were comparable to polypropylene. • The crosslinked nanocomposites can be biodegradable

  19. Isolated persistent left-sided superior vena cava, giant coronary sinus, atrial tachycardia and heart failure in a child

    Directory of Open Access Journals (Sweden)

    Nagaraja Moorthy

    2013-09-01

    Full Text Available Persistence of a left-sided superior vena cava (PLSVC with absent right superior vena cava (isolated PLSVC is a very rare venous malformation and commonly associated with congenital heart disease or alterations of the cardiac situs. We describe an unusual case of a young boy presenting with persistent atrial tachycardia and congestive heart failure. He was detected to have unexplained grossly dilated right atrium, right ventricle with systolic dysfunction and a giant coronary sinus (CS. The dilated CS closely mimicked a pseudo cor-triatriatum on echocardiography. Contrast echocardiography from both arms revealed opacification of the CS before the right atrium. Bilateral upper limb venography confirmed the presence of absent right SVC and isolated persistent left SVC draining into the giant coronary sinus.

  20. Tensile and morphology properties of PLA/LNR blends modified with maleic anhydride grafted-polylactic acid and -natural rubber

    Science.gov (United States)

    Ruf, Mohd Farid Hakim Mohd; Ahmad, Sahrim; Chen, Ruey Shan; Shahdan, Dalila; Zailan, Farrah Diyana

    2018-04-01

    This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid(PLA-g-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the tensile and morphology properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA was first self-synthesized using maleic anhydride (MA) and dicumyl peroxide (DCP) as initiator together with the PLA and NR respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via melt-blending method. The loading of PLA-g-MA and NR-g-MA was varied by 5, 10 and 15 wt% respectively. The addition of PLA-g-MA led to increment in tensile strength with 5 and 10 wt% while NR-g-MA gives lower than controlled sample (PLA/LNR blend). Scanning electron microscope (SEM) showed the interaction of the components in the blends. The PLA/LNR compatibilized with PLA-g-MA and NR-g-MA shows greater dispersion and adhesion.

  1. Photocrosslinked PLA-PEO-PLA Hydrogels from Self-Assembled Physical Networks: Mechanical Properties and Influence of Assumed Constitutive Relationships

    Science.gov (United States)

    Sanabria-DeLong, Naomi; Crosby, Alfred J.; Tew, Gregory N.

    2014-01-01

    Poly(lactide) – block – poly(ethylene oxide) – block – poly(lactide) [PLA-PEO-PLA] triblock copolymers are known to form physical hydrogels in water, due to the polymer's amphiphilicity. Their mechanical properties, biocompatibility, and biodegradability have made them attractive for use as soft tissue scaffolds. However, the network junction points are not covalently crosslinked and in a highly aqueous environment these hydrogels adsorb more water, transform from gel to sol, and lose the designed mechanical properties. In this report, a hydrogel was formed by using a novel two step approach. In the first step end-functionalized PLA-PEOPLA triblock was self-assembled into a physical hydrogel through hydrophobic micelle network junctions, and then, in the second step, this self-assembled physical network structure was locked into place by photocrosslinking the terminal acrylate groups. In contrast to physical hydrogels, the photocrosslinked gels remained intact in phosphate buffered solution at body temperature. The swelling, degradation, and mechanical properties were characterized and demonstrated extended degradation time (~ 65 days), exponential decrease in modulus with degradation time, and tunable shear modulus (1.6 – 133 kPa) by varying concentration. We also discuss the various constitutive relationships (Hookean, Neo-Hookean, and Mooney-Rivlin) that can be used to describe the stress-strain behavior of these hydrogels. The chosen model and assumptions used for data fitting influences the obtained modulus values by as much as a factor of 3.5, demonstrating the importance of clearly stating one's data fitting parameters so that accurate comparisons can be made within the literature. PMID:18817440

  2. Surface polish of PLA parts in FDM using dichloromethane vapour

    Directory of Open Access Journals (Sweden)

    Jin Yifan

    2017-01-01

    Full Text Available Fused deposition modelling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely limited by poor surface roughness. Thus it is necessary to adopt some operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modelling (FDM. The purpose of this paper is to decrease the surface roughness for polylactic acid (PLA parts in FDM. The chemical reaction mechanism during the treating process is analysed. Then NaOH solution and dichloromethane vapour are used to treat FDM specimens respectively. A 3D laser microscope has been applied to assess the effects in terms of surface topography and roughness. The experimental results show that treatment using dichloromethane vapour performs much better than NaOH solution. Compared with the untreated group, surface roughness obtained through vapour treatment decreases by 88 per cent. This research has been conducted to provide a better method to treat PLA parts using chemical reagents.

  3. PLA-PEG-PLA copolymer-based polymersomes as nanocarriers for delivery of hydrophilic and hydrophobic drugs: preparation and evaluation with atorvastatin and lisinopril.

    Science.gov (United States)

    Danafar, H; Rostamizadeh, K; Davaran, S; Hamidi, M

    2014-10-01

    Tri-block poly(lactide)-poly(ethylene glycol)-poly(lactide) (PLA-PEG-PLA) copolymers were synthesized and used to prepare polymersomes loaded separately by the hydrophobic and hydrophilic model drugs, atorvastatin and lisinopril, respectively. The resulting nanostructures were characterized by various techniques such as FTIR, DSC, PCS and AFM. The polymersomes exhibited high encapsulation efficiencies of almost 78% and 70.8% for atorvastatin and lisinopril, respectively. Investigation on FTIR and DSC results revealed that such a high encapsulation efficiency is due to strong interaction between atorvastatin and the copolymer. The impact of drug/copolymer ratio and copolymer composition on drug-loading efficiency and drug release behavior were also studied. The results showed that in case of lisinopril, polymersomes exhibited a triphasic drug release, while for atorvastatin a biphasic release profile was obtained. Overall, the results indicated that PLA-PEG-PLA polymersomes can be considered as a promising carrier for both hydrophilic and hydrophobic drugs.

  4. Potential of a newly developed high-speed near-infrared (NIR) camera (Compovision) in polymer industrial analyses: monitoring crystallinity and crystal evolution of polylactic acid (PLA) and concentration of PLA in PLA/Poly-(R)-3-hydroxybutyrate (PHB) blends.

    Science.gov (United States)

    Ishikawa, Daitaro; Nishii, Takashi; Mizuno, Fumiaki; Sato, Harumi; Kazarian, Sergei G; Ozaki, Yukihiro

    2013-12-01

    This study was carried out to evaluate a new high-speed hyperspectral near-infrared (NIR) camera named Compovision. Quantitative analyses of the crystallinity and crystal evolution of biodegradable polymer, polylactic acid (PLA), and its concentration in PLA/poly-(R)-3-hydroxybutyrate (PHB) blends were investigated using near-infrared (NIR) imaging. This NIR camera can measure two-dimensional NIR spectral data in the 1000-2350 nm region obtaining images with wide field of view of 150 × 250 mm(2) (approximately 100  000 pixels) at high speeds (in less than 5 s). PLA with differing crystallinities between 0 and 50% blended samples with PHB in ratios of 80/20, 60/40, 40/60, 20/80, and pure films of 100% PLA and PHB were prepared. Compovision was used to collect respective NIR spectra in the 1000-2350 nm region and investigate the crystallinity of PLA and its concentration in the blends. The partial least squares (PLS) regression models for the crystallinity of PLA were developed using absorbance, second derivative, and standard normal variate (SNV) spectra from the most informative region of the spectra, between 1600 and 2000 nm. The predicted results of PLS models achieved using the absorbance and second derivative spectra were fairly good with a root mean square error (RMSE) of less than 6.1% and a determination of coefficient (R(2)) of more than 0.88 for PLS factor 1. The results obtained using the SNV spectra yielded the best prediction with the smallest RMSE of 2.93% and the highest R(2) of 0.976. Moreover, PLS models developed for estimating the concentration of PLA in the blend polymers using SNV spectra gave good predicted results where the RMSE was 4.94% and R(2) was 0.98. The SNV-based models provided the best-predicted results, since it can reduce the effects of the spectral changes induced by the inhomogeneity and the thickness of the samples. Wide area crystal evolution of PLA on a plate where a temperature slope of 70-105 °C had occurred was also

  5. Corruption in the PLA: Retarding China’s Rise as a Great Power

    Science.gov (United States)

    2013-03-01

    operations across the entire PLA. The SD was charged to 9 investigate reports of unethical and corrupt behavior by uniformed officers of the PLA. Most...PLAN) who was investigated on bribery charges and having five mistresses. Ironically these charges were brought by one of his former mistresses

  6. DEGRADATION AND PROCESSING OF PLA AND ITS APPLICATION IN FIXATION OF BONE FRACTURE

    Institute of Scientific and Technical Information of China (English)

    HUYushan; BAIDongren; 等

    1999-01-01

    PLA is presently considered as the most attractive compound for temporary therapeutic application in the biomedical field.In this paper we give an overview of the present knowledge on the degradation behavior,processing technology of PLA and its application in the fixation of bone fracture.

  7. Research Maps New Routes for Reading Success in PLA Early Childhood Initiative.

    Science.gov (United States)

    Meyers, Elaine

    2002-01-01

    The Public Library Association (PLA) partnered with the National Institute of Child Health and Human Development (NICHD) to develop research-based tools for parents to prepare children for reading. Inherent in the materials is the major role of the public library in formation of readers. Outlines goals and activities (2001-2002) of the PLA/ALSC…

  8. PLA Philosophy, Policy, and Practice Implications: Revisiting the 2009 Hoffman, Travers, Evans, and Treadwell Study

    Science.gov (United States)

    Travers, Nan L.

    2013-01-01

    The heart of prior learning assessment (PLA) is the quality and validity of the academic evaluation process itself. Institutions providing PLA opportunities are faced with issues of accountability from all constituents: students, faculty, state systems, and accrediting agencies. Increasingly, institutions are more and more accepting of different…

  9. Holding Tight or at Arm's Length: How Higher Education Regional Accrediting Bodies Address PLA. Research Brief

    Science.gov (United States)

    Council for Adult and Experiential Learning, 2014

    2014-01-01

    Prior learning assessment (PLA) is the term used for the various ways in which higher education institutions and other organizations assess an individual's learning for the purposes of granting college credit, certification, or advanced standing in a postsecondary education program. In recent years, there has been growing interest in PLA from…

  10. Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch.

    Science.gov (United States)

    Wokadala, Obiro Cuthbert; Emmambux, Naushad Mohammad; Ray, Suprakas Sinha

    2014-11-04

    In this study, waxy and high amylose starches were modified through butyl-etherification to facilitate compatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and wettability tests showed that hydrophobic butyl-etherified waxy and high amylose starches were obtained with degree of substitution values of 2.0 and 2.1, respectively. Differential scanning calorimetry, tensile testing, and scanning electron microscopy (SEM) demonstrated improved PLA/starch compatibility for both waxy and high amylose starch after butyl-etherification. The PLA/butyl-etherified waxy and high amylose starch composite films had higher tensile strength and elongation at break compared to PLA/non-butyl-etherified composite films. The morphological study using SEM showed that PLA/butyl-etherified waxy starch composites had a more homogenous microstructure compared to PLA/butyl-etherified high amylose starch composites. Thermogravimetric analysis showed that PLA/starch composite thermal stability decreased with starch butyl-etherification for both waxy and high amylose starches. This study mainly demonstrates that PLA/starch compatibility can be improved through starch butyl-etherification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Complete regression of xenograft tumors using biodegradable mPEG-PLA-SN38 block copolymer micelles.

    Science.gov (United States)

    Lu, Lu; Zheng, Yan; Weng, Shuqiang; Zhu, Wenwei; Chen, Jinhong; Zhang, Xiaomin; Lee, Robert J; Yu, Bo; Jia, Huliang; Qin, Lunxiu

    2016-06-01

    7-Ethyl-10-hydroxy-comptothecin (SN38) is an active metabolite of irinotecan (CPT-11) and the clinical application of SN38 is limited by its hydrophobicity and instability. To address these issues, a series of novel amphiphilic mPEG-PLA-SN38-conjugates were synthesized by linking SN38 to mPEG-PLA-SA, and they could form micelles by self-assembly. The effects of mPEG-PLA composition were studied in vitro and in vivo. The mean diameters of mPEG2K-PLA-SN38 micelles and mPEG4K-PLA-SN38 micelles were 10-20nm and 120nm, respectively, and mPEG2K-PLA-SN38 micelles showed greater antitumor efficacy than mPEG4K-PLA-SN38 micelles both in vitro and in vivo. These data suggest that the lengths of mPEG and PLA chains had a major impact on the physicochemical characteristics and antitumor activity of SN38-conjugate micelles. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Production, characterisation, and in vitro nebulisation performance of budesonide-loaded PLA nanoparticles.

    Science.gov (United States)

    Amini, Mohammad Ali; Faramarzi, Mohammad Ali; Gilani, Kambiz; Moazeni, Esmaeil; Esmaeilzadeh-Gharehdaghi, Elina; Amani, Amir

    2014-01-01

    The aim of this study is to prepare a nanosuspension of budesonide for respiratory delivery using nebuliser by optimising its particle size and characterising its in vitro deposition behaviour. PLA (poly lactic acid)-budesonide nanosuspension (BNS) was prepared using high-pressure emulsification/solvent evaporation method. To optimise particle size, different parameters such as PLA concentration, sonication time, and amplitude were investigated. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscope (SEM) analyses were performed to characterise the prepared PLA-budesonide nanoparticles. The in vitro aerodynamic characteristics of the PLA-BNS using a jet nebuliser were estimated and compared with that of commercially available suspension formulation of budesonide. Budesonide-loaded PLA nanoparticles with fine particle size (an average size of 224-360 nm), narrow size distribution, and spherical and smooth surface were prepared. The optimum condition for preparation of fine particle size for aerosolisation was found to be at PLA concentration of 1.2 mg/ml and amplitude of 70 for 75 s sonication time. The in vitro aerosolisation performance of PLA-BNS compared to that of commercial budesonide indicated that it has significantly (p PLA-BNS could be considered as a promising alternative suspension formulation for deep lung delivery of the drug using nebuliser.

  13. Moving the Starting Line through Prior Learning Assessment (PLA). Research Brief

    Science.gov (United States)

    Council for Adult and Experiential Learning (NJ1), 2011

    2011-01-01

    Prior learning assessment (PLA) methods can help adult students earn college credit for what they already know. PLA can be an important offering by postsecondary degree programs because it can save students time and money. In addition, the Council for Adult and Experiential Learning's (CAEL's) "Fueling the Race to Postsecondary Success"…

  14. Supertoughened renewable PLA reactive multiphase blends system: phase morphology and performance.

    Science.gov (United States)

    Zhang, Kunyu; Nagarajan, Vidhya; Misra, Manjusri; Mohanty, Amar K

    2014-08-13

    Multiphase blends of poly(lactic acid) (PLA), ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer, and a series of renewable poly(ether-b-amide) elastomeric copolymer (PEBA) were fabricated through reactive melt blending in an effort to improve the toughness of the PLA. Supertoughened PLA blend showing impact strength of ∼500 J/m with partial break impact behavior was achieved at an optimized blending ratio of 70 wt % PLA, 20 wt % EMA-GMA, and 10 wt % PEBA. Miscibility and thermal behavior of the binary blends PLA/PEBA and PLA/EMA-GMA, and the multiphase blends were also investigated through differential scanning calorimetric (DSC) and dynamic mechanical analysis (DMA). Phase morphology and fracture surface morphology of the blends were studied through scanning electron microscopy (SEM) and atomic force microscopy (AFM) to understand the strong corelation between the morphology and its significant effect on imparting tremendous improvement in toughness. A unique "multiple stacked structure" with partial encapsulation of EMA-GMA and PEBA minor phases was observed for the PLA/EMA-GMA/PEBA (70/20/10) revealing the importance of particular blend composition in enhancing the toughness. Toughening mechanism behind the supertoughened PLA blends have been established by studying the impact fractured surface morphology at different zones of fracture. Synergistic effect of good interfacial adhesion and interfacial cavitations followed by massive shear yielding of the matrix was believed to contribute to the enormous toughening effect observed in these multiphase blends.

  15. Degradation of polylactic acid (Pla) at different doses of gamma radiation; Degradacion del acido polilactico (PLA) a diferentes dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Castillo R, Y.

    2015-07-01

    The excessive use of polymers such as polyethylene (PET), polystyrene (Ps) and recently the polylactic acid (Pla) that take more than 20 years to degrade, have caused great pollution in the environment. In this study the effects of gamma radiation in the Pla to different doses were studied, in order to reduce the degradation time of this polymer. The changes in physico-chemical structure of Pla during radiation were studied by thermo-gravimetric/Mass analysis; differential scanning calorimetry; scanning electron microscopy; X-ray dispersive analysis; infrared spectroscopy; X-ray diffraction and mechanical tests of hardness, elasticity and deformation. With scanning electron microscopy, the morphology of the Pla surface unirradiated was observed, in which an apparently smooth surface was observed, after changes that had the Pla when irradiated also was observed, where the effects of radiation were observed in form of scratch, agglomeration and small fractures. By X-ray dispersive analysis was determined and verified the elemental chemical composition of the Pla; as expected the tests showed only carbon, oxygen and hydrogen. With thermo-gravimetric/Mass analysis the decomposition temperatures of Pla were determined, identifying that the degradation compounds are CO, CO{sub 2} and CH{sub 4}. With infrared spectrometry the major peaks of Pla were observed before and after being irradiated with increasing of radiation dose the intensity of the bands decreased. Also by X-ray diffraction was observed that the polymer is an amorphous material. The mechanical tests indicate that the values of each of the tests decrease significantly with increasing the radiation dose. (Author)

  16. Influence of the Formulation Parameters on the Particle Size and Encapsulation Efficiency of Resveratrol in PLA and PLA-PEG Blend Nanoparticles: A Factorial Design.

    Science.gov (United States)

    Lindner, Gabriela da Rocha; Dalmolin, Luciana Facco; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

    2015-12-01

    Polymeric nanoparticles are colloidal systems that promote protection and modification of physicochemical characteristics of a drug and that also ensure controlled and extended drug release. This paper reports a 2(3) factorial design study to optimize poly(lactide) (PLA) and poly(lactide)-polyethylene glycol (PLA-PEG) blend nanoparticles containing resveratrol (RVT) for prolonged release. The independent variables analyzed were solvent composition, surfactant concentration and ratio of aqueous to organic phase (two levels each factor). Mean particle size and RVT encapsulation efficiency were set as the dependent variables. The selected optimized parameters were set as organic phase comprised of a mixture of dichloromethane and ethyl acetate, 1% of surfactant polyvinyl alcohol and a 3:1 ratio of aqueous to organic phase, for both PLA and PLA-PEG blend nanoparticles. This formulation originated nanoparticles with size of 228 ± 10 nm and 185 ± 70 nm and RVT encapsulation efficiency of 82 ± 10% and 76 ± 7% for PLA and PLA-PEG blend nanoparticles, respectively. The in vitro release study showed a biphasic pattern with prolonged RVT release and PEG did not influence the RVT release. The in vitro release data were in favor of Higuchi-diffusion kinetics for both nanoformulations and the Kossmeyer-Peppas coefficient indicated that anomalous transport was the main release mechanism of RVT. PLA and PLA-PEG blend nanoparticles produced with single emulsion-solvent evaporation technology were found to be a promising approach for the incorporation of RVT and promoted its controlled release. The factorial design is a tool of great value in choosing formulations with optimized parameters.

  17. Effect of organo clay addition on thermal properties of poly lactide/ polycaprolactone (PLA/ PCL) nano composites

    International Nuclear Information System (INIS)

    Siti Zulaiha Hairaldin; Wan Md Zin Wan Yunus; Norazoma Ibrahim

    2010-01-01

    In this study, melt blending technique was applied to prepare poly lactide/polycaprolactone (PLA/ PCL) nano composites with various blends. Montmorillonite (MMT) was used as an addition to the matrix. In this study, melt blending technique was applied to prepare poly lactide/polycaprolactone (PLA/ PCL) nano composites. Montmorillonite (MMT) was used as an addition to the matrix with various percentages. The other one is modified clay prepared by modifying the nature of montmorillonite with octadecylamine (ODA) to improve the characteristic of PLA/ PCL blends. X-ray diffraction (XRD) results indicated intercalation of the PLA/ PCL into silicate nano size interlayers galleries of the nano composites. The presence of modified clays in nano composite was confirmed by FTIR spectrum. TGA and DTG results show addition of MMT and modified clay ODA-MMT improved the thermal stability of the PLA/ PCL blends. (author)

  18. Snake Venom PLA2, a Promising Target for Broad-Spectrum Antivenom Drug Development

    Directory of Open Access Journals (Sweden)

    Huixiang Xiao

    2017-01-01

    Full Text Available Snakebite envenomation is a neglected global health problem, causing substantial mortality, disability, and psychological morbidity, especially in rural tropical and subtropical zones. Antivenin is currently the only specific medicine for envenomation. However, it is restricted by cold storage, snakebite diagnosis, and high price. Snake venom phospholipase A2s (svPLA2s are found in all kinds of venomous snake families (e.g., Viperidae, Elapidae, and Colubridae. Along with their catalytic activity, svPLA2s elicit a wide variety of pharmacological effects that play a pivotal role in envenomation damage. Hence, neutralization of the svPLA2s could weaken or inhibit toxic damage. Here we overviewed the latest knowledge on the distribution, pathophysiological effects, and inhibitors of svPLA2s to elucidate the potential for a novel, wide spectrum antivenom drug targeting svPLA2s.

  19. Bionanocomposite films based on plasticized PLA-PHB/cellulose nanocrystal blends.

    Science.gov (United States)

    Arrieta, M P; Fortunati, E; Dominici, F; López, J; Kenny, J M

    2015-05-05

    Optically transparent plasticized poly(lactic acid) (PLA) based bionanocomposite films intended for food packaging were prepared by melt blending. Materials were plasticized with 15wt% of acetyl(tributyl citrate) (ATBC) to improve the material processability and to obtain flexibile films. Poly(hydroxybutyrate) (PHB) was used to increase PLA crystallinity. The thermal stability of the PLA-PHB blends was improved by the addition of 5 wt% of cellulose nanocrystals (CNC) or modified cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose. The combination of ATBC and cellulose nanocrystals, mainly the better dispersed CNCs, improved the interaction between PLA and PHB. Thus, an improvement on the oxygen barrier and stretchability was achieved in PLA-PHB-CNCs-ATBC which also displayed somewhat UV light blocking effect. All bionanocomposite films presented appropriate disintegration in compost suggesting their possible applications as biodegradable packaging materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Revisiting the use of sPLA2-sensitive liposomes in cancer therapy

    DEFF Research Database (Denmark)

    Pourhassan, Houman; Clergeaud Veiga, Gael; Hansen, Anders Elias

    2017-01-01

    The first developed secretory phospholipase A2 (sPLA2) sensitive liposomal cisplatin formulation (LiPlaCis®) is currently undergoing clinical evaluation. In the present study we revisit and evaluate critical preclinical parameters important for the therapeutic potential and safety of platinum drugs......, here oxaliplatin (L-OHP), formulated in sPLA2 sensitive liposomes. We show the mole percentage of negatively charged phospholipid needed to obtain enzyme-sensitivity for saturated systems is ≥ 25% for 16-carbon chain lipid membranes, and > 40% for 18-chain lipid membranes, which was surprising as 25......% is used clinically in LiPlaCis®. Efficient sPLA2-dependent growth inhibition of colorectal cancer cells was demonstrated in vitro, where cell membrane degradation and cytolysis depends on the sensitivity of the formulation towards the enzyme and is governed by the amount of lysolipids generated...

  1. Development and characterization of novel antimicrobial bilayer films based on Polylactic acid (PLA)/Pickering emulsions.

    Science.gov (United States)

    Zhu, Jun-You; Tang, Chuan-He; Yin, Shou-Wei; Yang, Xiao-Quan

    2018-02-01

    Biodegradable food packaging is sustainable and has a great application prospect. PLA is a promising alternative for petroleum-derived polymers. However, PLA packaging suffers from poor barrier properties compared with petroleum-derived ones. To address this issue, we designed bilayer films based on PLA and Pickering emulsions. The formed bilayer films were compact and uniform and double layers were combined firmly. This strategy enhanced mechanical resistance, ductility and moisture barrier of Pickering emulsion films, and concomitantly enhanced the oxygen barrier for PLA films. Thymol loadings in Pickering emulsion layer endowed them with antimicrobial and antioxidant activity. The release profile of thymol was well fitted with Fick's second law. The antimicrobial activity of the films depended on film types, and Pickering emulsion layer presented larger inhibition zone than PLA layer, hinting that the films possessed directional releasing role. This study opens a promising route to fabricate bilayer architecture creating synergism of each layer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The role of cPLA2 in Methylglyoxal-induced cell apoptosis of HUVECs

    International Nuclear Information System (INIS)

    Yuan, Jie; Zhu, Chao; Hong, Yali; Sun, Zongxing; Fang, Xianjun; Wu, Biao; Li, Shengnan

    2017-01-01

    Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is mainly formed as a byproduct of glycolysis. Elevated MGO level is known to induce apoptosis of vascular endothelial cells, which is implicated with progression of atherosclerosis and diabetic complications. However, the underlying mechanisms have not been exhaustively investigated yet. Here, we further characterized the mechanisms how MGO induced apoptosis in human umbilical vein endothelial cells (HUVECs). Our data revealed that cytosolic phospholipase A2 (cPLA2) played an important role in MGO-induced cell apoptosis. It was found that MGO could increase both the activity and expression of cPLA2. Inhibition of cPLA2 by Pyrrophenone (PYR) or siRNA significantly attenuated the MGO-induced apoptosis. Additionally, MGO time-dependently decreased the phosphorylation of nuclear factor κB (NF-κB). Pretreatment of the cells with NF-κB inhibitor, BAY11-7082, further increased MGO-induced apoptosis of HUVECs, indicating that NF-κB played a survival role in this MGO-induced apoptosis. Furthermore, in the presence of si-cPLA2 or PYR, MGO no longer decreased NF-κB phosphorylation. Beyond that, the antioxidant N-acetyl cysteine (NAC) could reverse the changes of both cPLA2 and NF-κB caused by MGO. p38, the upstream of cPLA2, was also significantly phosphorylated by MGO. However, p38 inhibitor failed to reverse the apoptosis induced by MGO. This study gives an important insight into the downstream signaling mechanisms of MGO, cPLA2-NF-κB, in endothelial apoptosis. - Highlights: • cPLA2 participated in MGO-induced HUVECs apoptosis. • Inhibition of NF-κB was involved in MGO-cPLA2-mediated cell apoptosis. • Antioxidant NAC attenuated MGO-induced cPLA2 activation and cell apoptosis.

  3. The role of cPLA2 in Methylglyoxal-induced cell apoptosis of HUVECs

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Jie; Zhu, Chao; Hong, Yali; Sun, Zongxing; Fang, Xianjun [Jiangsu Provincial Key Lab of Cardiovascular Diseases and Molecular intervention, Department of Pharmacology, Nanjing Medical University, Nanjing 210029 (China); Wu, Biao, E-mail: wubiao@ncu.edu.cn [Department of Surgery, The First Affiliated Hospital, Nanchang University (China); Li, Shengnan, E-mail: snli@njmu.edu.cn [Jiangsu Provincial Key Lab of Cardiovascular Diseases and Molecular intervention, Department of Pharmacology, Nanjing Medical University, Nanjing 210029 (China)

    2017-05-15

    Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is mainly formed as a byproduct of glycolysis. Elevated MGO level is known to induce apoptosis of vascular endothelial cells, which is implicated with progression of atherosclerosis and diabetic complications. However, the underlying mechanisms have not been exhaustively investigated yet. Here, we further characterized the mechanisms how MGO induced apoptosis in human umbilical vein endothelial cells (HUVECs). Our data revealed that cytosolic phospholipase A2 (cPLA2) played an important role in MGO-induced cell apoptosis. It was found that MGO could increase both the activity and expression of cPLA2. Inhibition of cPLA2 by Pyrrophenone (PYR) or siRNA significantly attenuated the MGO-induced apoptosis. Additionally, MGO time-dependently decreased the phosphorylation of nuclear factor κB (NF-κB). Pretreatment of the cells with NF-κB inhibitor, BAY11-7082, further increased MGO-induced apoptosis of HUVECs, indicating that NF-κB played a survival role in this MGO-induced apoptosis. Furthermore, in the presence of si-cPLA2 or PYR, MGO no longer decreased NF-κB phosphorylation. Beyond that, the antioxidant N-acetyl cysteine (NAC) could reverse the changes of both cPLA2 and NF-κB caused by MGO. p38, the upstream of cPLA2, was also significantly phosphorylated by MGO. However, p38 inhibitor failed to reverse the apoptosis induced by MGO. This study gives an important insight into the downstream signaling mechanisms of MGO, cPLA2-NF-κB, in endothelial apoptosis. - Highlights: • cPLA2 participated in MGO-induced HUVECs apoptosis. • Inhibition of NF-κB was involved in MGO-cPLA2-mediated cell apoptosis. • Antioxidant NAC attenuated MGO-induced cPLA2 activation and cell apoptosis.

  4. Modification of cellulose nanocrystals (CNCs) for use in poly(lactic acid) (PLA)-CNC composite packaging products

    Science.gov (United States)

    Liqing Wei; Nicole M. Stark; Ronald C. Sabo; Laurent Matuana

    2016-01-01

    There is growing interest in developing bio-based materials for packaging. Bio-derived materials such as cellulose nanocrystals (CNCs) and poly(lactic acid) (PLA) can be used to develop sustainable packaging applications. Incorporating CNCs into PLA can increase the crystallinity and barrier properties of PLA. The challenge lies in both increasing the flexibility of...

  5. Graphene oxide stabilized by PLA-PEG copolymers for the controlled delivery of paclitaxel.

    Science.gov (United States)

    Angelopoulou, A; Voulgari, E; Diamanti, E K; Gournis, D; Avgoustakis, K

    2015-06-01

    To investigate the application of water-dispersible poly(lactide)-poly(ethylene glycol) (PLA-PEG) copolymers for the stabilization of graphene oxide (GO) aqueous dispersions and the feasibility of using the PLA-PEG stabilized GO as a delivery system for the potent anticancer agent paclitaxel. A modified Staudenmaier method was applied to synthesize graphene oxide (GO). Diblock PLA-PEG copolymers were synthesized by ring-opening polymerization of dl-lactide in the presence of monomethoxy-poly(ethylene glycol) (mPEG). Probe sonication in the presence of PLA-PEG copolymers was applied in order to reduce the hydrodynamic diameter of GO to the nano-size range according to dynamic light scattering (DLS) and obtain nano-graphene oxide (NGO) composites with PLA-PEG. The composites were characterized by atomic force microscopy (AFM), thermogravimetric analysis (TGA), and DLS. The colloidal stability of the composites was evaluated by recording the size of the composite particles with time and the resistance of composites to aggregation induced by increasing concentrations of NaCl. The composites were loaded with paclitaxel and the in vitro release profile was determined. The cytotoxicity of composites against A549 human lung cancer cells in culture was evaluated by flow cytometry. The uptake of FITC-labeled NGO/PLA-PEG by A549 cells was also estimated with flow cytometry and visualized with fluorescence microscopy. The average hydrodynamic diameter of NGO/PLA-PEG according to DLS ranged between 455 and 534 nm, depending on the molecular weight and proportion of PLA-PEG in the composites. NGO/PLA-PEG exhibited high colloidal stability on storage and in the presence of high concentrations of NaCl (far exceeding physiological concentrations). Paclitaxel was effectively loaded in the composites and released by a highly sustained fashion. Drug release could be regulated by the molecular weight of the PLA-PEG copolymer and its proportion in the composite. The paclitaxel

  6. Characterization of LDPE/PBAT/PLA and organophilic bentonite nanocomposites

    International Nuclear Information System (INIS)

    Figueredo, Daniela Casimiro de; Viana, Hamilton; Rosa, Derval dos Santos; Poveda, Patricia Negrini Siqueira

    2011-01-01

    Due to the ascension of Green chemistry in the 90's, it has been a demand for the production of biodegradable materials which cause minimal impacts to environment. Some nanocomposites are in this material class. In this context, six formulations containing low density polyethylene (LDPE), a compatibilized commercial poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) blend under the trademark Ecovio and organophilic bentonite were processed by extrusion to make films which were characterized by X-ray diffraction, melt flow index (MFI) and mechanical tests. X- ray pattern revealed that the nano clay was composed predominantly of montmorillonite, quartz and kaolinite and it could promote formation of intercalated or exfoliated composites. Nano clay also affected the fluidity of composites with variations in module up to 4%, as evidenced by melt flow index. Mechanical tests demonstrated that there was no uniformity in mechanical behavior of the nanocomposites. (author)

  7. Novel genetic approach to investigate the role of plasma secretory phospholipase A2 (sPLA2)-V isoenzyme in coronary heart disease: modified Mendelian randomization analysis using PLA2G5 expression levels.

    Science.gov (United States)

    Holmes, Michael V; Exeter, Holly J; Folkersen, Lasse; Nelson, Christopher P; Guardiola, Montse; Cooper, Jackie A; Sofat, Reecha; Boekholdt, S Matthijs; Khaw, Kay-Tee; Li, Ka-Wah; Smith, Andrew J P; Van't Hooft, Ferdinand; Eriksson, Per; Franco-Cereceda, Anders; Asselbergs, Folkert W; Boer, Jolanda M A; Onland-Moret, N Charlotte; Hofker, Marten; Erdmann, Jeanette; Kivimaki, Mika; Kumari, Meena; Reiner, Alex P; Keating, Brendan J; Humphries, Steve E; Hingorani, Aroon D; Mallat, Ziad; Samani, Nilesh J; Talmud, Philippa J

    2014-04-01

    Secretory phospholipase A2 (sPLA2) enzymes are considered to play a role in atherosclerosis. sPLA2 activity encompasses several sPLA2 isoenzymes, including sPLA2-V. Although observational studies show a strong association between elevated sPLA2 activity and CHD, no assay to measure sPLA2-V levels exists, and the only evidence linking the sPLA2-V isoform to atherosclerosis progression comes from animal studies. In the absence of an assay that directly quantifies sPLA2-V levels, we used PLA2G5 mRNA levels in a novel, modified Mendelian randomization approach to investigate the hypothesized causal role of sPLA2-V in coronary heart disease (CHD) pathogenesis. Using data from the Advanced Study of Aortic Pathology, we identified the single-nucleotide polymorphism in PLA2G5 showing the strongest association with PLA2G5 mRNA expression levels as a proxy for sPLA2-V levels. We tested the association of this SNP with sPLA2 activity and CHD events in 4 prospective and 14 case-control studies with 27 230 events and 70 500 controls. rs525380C>A showed the strongest association with PLA2G5 mRNA expression (P=5.1×10(-6)). There was no association of rs525380C>A with plasma sPLA2 activity (difference in geometric mean of sPLA2 activity per rs525380 A-allele 0.4% (95% confidence intervals [-0.9%, 1.6%]; P=0.56). In meta-analyses, the odds ratio for CHD per A-allele was 1.02 (95% confidence intervals [0.99, 1.04]; P=0.20). This novel approach for single-nucleotide polymorphism selection for this modified Mendelian randomization analysis showed no association between rs525380 (the lead single-nucleotide polymorphism for PLA2G5 expression, a surrogate for sPLA2-V levels) and CHD events. The evidence does not support a causal role for sPLA2-V in CHD.

  8. Analysis and prediction of daylighting and energy performance in atrium spaces using daylight-linked lighting controls

    International Nuclear Information System (INIS)

    Chow, Stanley K.H.; Li, Danny H.W.; Lee, Eric W.M.; Lam, Joseph C.

    2013-01-01

    Highlights: ► Daylight-linked lighting control and energy performance for atrium is studied. ► Field measurement of automatic dimming control shows 93% energy saving. ► Field measurement of manual on–off control shows 95% energy saving. ► Atrium illuminance is correlated with daylight factor for energy saving prediction. - Abstract: In subtropical Hong Kong, a certain amount of electricity is used to create visually comfortable interior spaces through electric lighting, which is the second major electricity-consuming item in commercial buildings, accounting for 20–30% of total electricity use. The burning of fossil fuels for electricity generation has many adverse effects on the environment. Daylighting is an important and useful strategy for enhancing visual comfort and reducing the need for the electricity consumed by light fittings. The rational use of daylight through tools such as photoelectric lighting controls can effectively reduce buildings’ electricity consumption and the related pollutants and greenhouse gas emissions. Daylighting design techniques are often best demonstrated via field measurements that provide reliable operational and energy performance data for establishing design guidelines. An atrium provides an environmentally controlled indoor public space that introduces daylight into the hearts of large buildings. In circulation areas such as corridors, people expect the way ahead to be sufficiently lit and daylight-linked lighting controls can deliver excellent energy savings. This paper presents the daylighting and energy performance of an atrium space using daylight-linked lighting controls. The cost, energy and environmental issues related to various daylight illuminances are estimated and design implications are discussed

  9. Optimizing computed tomography pulmonary angiography using right atrium bolus monitoring combined with spontaneous respiration

    Energy Technology Data Exchange (ETDEWEB)

    Min, Wang; Jian, Li; Rui, Zhai [Jining No. 1 People' s Hospital, Department of Computed Tomography, Jining City, ShanDong Province (China); Wen, Li [Jining No. 1 People' s Hospital, Department of Gastroenterology, Jining, ShanDong (China); Dai, Lun-Hou [Shandong Chest Hospital, Department of Radiology, Jinan, ShanDong (China)

    2015-09-15

    CT pulmonary angiography (CTPA) aims to provide pulmonary arterial opacification in the absence of significant pulmonary venous filling. This requires accurate timing of the imaging acquisition to ensure synchronization with the peak pulmonary artery contrast concentration. This study was designed to test the utility of right atrium (RA) monitoring in ensuring optimal timing of CTPA acquisition. Sixty patients referred for CTPA were divided into two groups. Group A (n = 30): CTPA was performed using bolus triggering from the pulmonary trunk, suspended respiration and 70 ml of contrast agent (CA). Group B (n = 30): CTPA image acquisition was triggered using RA monitoring with spontaneous respiration and 40 ml of CA. Image quality was compared. Subjective image quality, average CT values of pulmonary arteries and density difference between artery and vein pairs were significantly higher whereas CT values of pulmonary veins were significantly lower in group B (all P < 0.05). There was no significant difference between the groups in the proportion of subjects where sixth grade pulmonary arteries were opacified (P > 0.05). RA monitoring combined with spontaneous respiration to trigger image acquisition in CTPA produces optimal contrast enhancement in pulmonary arterial structures with minimal venous filling even with reduced doses of CA. (orig.)

  10. Simultaneous Epicardial and Noncontact Endocardial Mapping of the Canine Right Atrium: Simulation and Experiment

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J. Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals. PMID:24598778

  11. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals.

  12. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Directory of Open Access Journals (Sweden)

    Sepideh Sabouri

    Full Text Available Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes, noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter, and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression, activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa, a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments and 0.96 (simulation between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments and 0.92 (simulation between ATa values. Despite distance (balloon-atrial wall and dimension reduction (64 electrodes, some information about atrial repolarization remained present in noncontact signals.

  13. Additive Manufacturing and Characterization of Polylactic Acid (PLA) Composites Containing Metal Reinforcements

    Science.gov (United States)

    Kuentz, Lily; Salem, Anton; Singh, M.; Halbig, M. C.; Salem, J. A.

    2016-01-01

    Additive manufacturing of polymeric systems using 3D printing has become quite popular recently due to rapid growth and availability of low cost and open source 3D printers. Two widely used 3D printing filaments are based on polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) systems. PLA is much more environmentally friendly in comparison to ABS since it is made from renewable resources such as corn, sugarcane, and other starches as precursors. Recently, polylactic acid-based metal powder containing composite filaments have emerged which could be utilized for multifunctional applications. The composite filaments have higher density than pure PLA, and the majority of the materials volume is made up of polylactic acid. In order to utilize functionalities of composite filaments, printing behavior and properties of 3-D printed composites need to be characterized and compared with the pure PLA materials. In this study, pure PLA and composite specimens with different metallic reinforcements (Copper, Bronze, Tungsten, Iron, etc) were 3D printed at various layer heights and resulting microstructures and properties were characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) behavior of filaments with different reinforcements were studied. The microscopy results show an increase in porosity between 3-D printed regular PLA and the metal composite PLA samples, which could produce weaker mechanical properties in the metal composite materials. Tensile strength and fracture toughness behavior of specimens as a function of print layer height will be presented.

  14. Putrescine importer PlaP contributes to swarming motility and urothelial cell invasion in Proteus mirabilis.

    Science.gov (United States)

    Kurihara, Shin; Sakai, Yumi; Suzuki, Hideyuki; Muth, Aaron; Phanstiel, Otto; Rather, Philip N

    2013-05-31

    Previously, we reported that the speA gene, encoding arginine decarboxylase, is required for swarming in the urinary tract pathogen Proteus mirabilis. In addition, this previous study suggested that putrescine may act as a cell-to-cell signaling molecule (Sturgill, G., and Rather, P. N. (2004) Mol. Microbiol. 51, 437-446). In this new study, PlaP, a putative putrescine importer, was characterized in P. mirabilis. In a wild-type background, a plaP null mutation resulted in a modest swarming defect and slightly decreased levels of intracellular putrescine. In a P. mirabilis speA mutant with greatly reduced levels of intracellular putrescine, plaP was required for the putrescine-dependent rescue of swarming motility. When a speA/plaP double mutant was grown in the presence of extracellular putrescine, the intracellular levels of putrescine were greatly reduced compared with the speA mutant alone, indicating that PlaP functioned as the primary putrescine importer. In urothelial cell invasion assays, a speA mutant exhibited a 50% reduction in invasion when compared with wild type, and this defect could be restored by putrescine in a PlaP-dependent manner. The putrescine analog Triamide-44 partially inhibited the uptake of putrescine by PlaP and decreased both putrescine stimulated swarming and urothelial cell invasion in a speA mutant.

  15. In vitro degradation of a 3D porous Pennisetum purpureum/PLA biocomposite scaffold.

    Science.gov (United States)

    Revati, R; Majid, M S Abdul; Ridzuan, M J M; Basaruddin, K S; Rahman Y, M N; Cheng, E M; Gibson, A G

    2017-10-01

    The in vitro degradation and mechanical properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA)-based scaffold were investigated. In this study, composite scaffolds with PP to PLA ratios of 0%, 10%, 20%, and 30% were immersed in a PBS solution at 37°C for 40 days. Compression tests were conducted to evaluate the compressive strength and modulus of the scaffolds, according to ASTM F451-95. The compression strength of the scaffolds was found to increase from 1.94 to 9.32MPa, while the compressive modulus increased from 1.73 to 5.25MPa as the fillers' content increased from 0wt% to 30wt%. Moreover, field emission scanning electron microscopy (FESEM) and X-ray diffraction were employed to observe and analyse the microstructure and fibre-matrix interface. Interestingly, the degradation rate was reduced for the PLA/PP 20 scaffold, though insignificantly, this could be attributed to the improved mechanical properties and stronger fibre-matrix interface. Microstructure changes after degradation were observed using FESEM. The FESEM results indicated that a strong fibre-matrix interface was formed in the PLA/PP 20 scaffold, which reflected the addition of P. purpureum into PLA decreasing the degradation rate compared to in pure PLA scaffolds. The results suggest that the P. purpureum/PLA scaffold degradation rate can be altered and controlled to meet requirements imposed by a given tissue engineering application. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Physical and mechanical properties of PLA, and their functions in widespread applications - A comprehensive review.

    Science.gov (United States)

    Farah, Shady; Anderson, Daniel G; Langer, Robert

    2016-12-15

    Poly(lactic acid) (PLA), so far, is the most extensively researched and utilized biodegradable aliphatic polyester in human history. Due to its merits, PLA is a leading biomaterial for numerous applications in medicine as well as in industry replacing conventional petrochemical-based polymers. The main purpose of this review is to elaborate the mechanical and physical properties that affect its stability, processability, degradation, PLA-other polymers immiscibility, aging and recyclability, and therefore its potential suitability to fulfill specific application requirements. This review also summarizes variations in these properties during PLA processing (i.e. thermal degradation and recyclability), biodegradation, packaging and sterilization, and aging (i.e. weathering and hygrothermal). In addition, we discuss up-to-date strategies for PLA properties improvements including components and plasticizer blending, nucleation agent addition, and PLA modifications and nanoformulations. Incorporating better understanding of the role of these properties with available improvement strategies is the key for successful utilization of PLA and its copolymers/composites/blends to maximize their fit with worldwide application needs. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Fracture Surface Morphology and Impact Strength of Cellulose/PLA Composites.

    Science.gov (United States)

    Gao, Honghong; Qiang, Tao

    2017-06-07

    Polylactide (PLA)-based composite materials reinforced with ball-milled celluloses were manufactured by extrusion blending followed by injection molding. Their surface morphology from impact fracture were imaged with scanning electron microscopy (SEM) and investigated by calculating their fractal dimensions. Then, linear regression was used to explore the relationship between fractal dimension and impact strength of the resultant cellulose/PLA composite materials. The results show that filling the ball-milled celluloses into PLA can improve the impact toughness of PLA by a minimum of 38%. It was demonstrated that the fracture pattern of the cellulose/PLA composite materials is different from that of pristine PLA. For the resultant composite materials, the fractal dimension of the impact fractured surfaces increased with increasing filling content and decreasing particle size of the ball-milled cellulose particles. There were highly positive correlations between fractal dimension of the fractured surfaces and impact strength of the cellulose/PLA composites. However, the linearity between fractal dimension and impact strength were different for the different methods, due to their different R-squared values. The approach presented in this work will help to understand the structure-property relationships of composite materials from a new perspective.

  18. Relationship between compatibilizer and yield strength of PLA/PP Blend

    Science.gov (United States)

    Jariyakulsith, Pattanun; Puajindanetr, Somchai

    2018-01-01

    The aim of this research is to study the relationship between compatibilizer and yield strength of polylactic acid (PLA) and polypropylene (PP) blend. The PLA is blended with PP (PLA/PP) at the ratios of 70/30, 50/50 and 30/70. In addition, (1) polypropylene grafted maleic anhydride (PP-g-MAH) as a compatibilizer at 0.3 and 0.7 part per hundred of PLA/PP resin (phr) and (2) dicumyl peroxide (DCP) being an initiator at 0.03 and 0.07 phr are added in each composition. Yield strength is characterized to study the interaction between compatibilizer, initiator and yield strength by using experimental design of multilevel full factorial. The results show that (1) the yield strength of PLA/PP blend are increased after addition of compatibilizer. Because the adding of PP-g-MAH and DCP resulted in improving compatibility between PLA and PP. (2) there are interaction between PP-g-MAH and DCP that have affected the final properties of PLA/PP blend. The highest yield strength of 27.68 MPa is provided at the ratio of 70/30 blend by using the 0.3 phr of PP-g-MAH and 0.03 phr of DCP. Linear regression model is fitted and follow the assumptions of normal distribution.

  19. Genetic invalidation of Lp-PLA2 as a therapeutic target

    DEFF Research Database (Denmark)

    Gregson, John M; Freitag, Daniel F; Surendran, Praveen

    2017-01-01

    AIMS: Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A2 (Lp-PLA2), has not reduced risk of cardiovascular disease outcomes in recent randomized trials. We aimed to test whether Lp-PLA2 enzyme activity is causally relevant to coronary heart disease. METHODS: In 72...... (Val379Ala (rs1051931)) in PLA2G7, the gene encoding Lp-PLA2. We supplemented de-novo genotyping with information on a further 45,823 coronary heart disease patients and 88,680 controls in publicly available databases and other previous studies. We conducted a systematic review of randomized trials...... to compare effects of darapladib treatment on soluble Lp-PLA2 activity, conventional cardiovascular risk factors, and coronary heart disease risk with corresponding effects of Lp-PLA2-lowering alleles. RESULTS: Lp-PLA2 activity was decreased by 64% (p = 2.4 × 10(-25)) with carriage of any of the four loss...

  20. Etiologic significance of enlargement of the left atrial appendage in adults

    International Nuclear Information System (INIS)

    Green, C.E.; Kelley, M.J.; Higgins, C.B.

    1982-01-01

    Fifty-one patients were divided into two groups: 20 patients with proven rheumatic mitral valve disease (RMVD) and 31 patients with left atrial enlargement (LAE) of a nonrheumatic etiology. The latter group included patients with ischemic papillary muscle dysfunction, mitral valve prolapse, and congestive cardiomyopathy. Radiographic studies showed that enlargement of the left atrial appendage (LAAE) was present in 18 of 20 rheumatics but in only one of 31 nonrheumatics. There was no direct relationship between enlargement of the LAA and radiographic or echocardiographic left atrial size, degree of pulmonary venous hypertension (PVH), or presence of atrial fibrillation. It is postulated that rheumatic influammation of the LAA allows it to dilate out of proportion to the body of the left atrium. In the adult patient with radiographic findings of PVH, LAAE is a valuable and specific radiographic sign of rheumatic mitral valve disease

  1. Use of the Amplatzer ASD Occluder for Closing a Persistent Left Vertical Vein

    International Nuclear Information System (INIS)

    Zanchetta, Mario; Zennaro, Marco; Zecchel, Roberto; Mancuso, Daniela; Pedon, Luigi

    2009-01-01

    We report the case of a very large anomalous connection of the veins draining the upper lobe of the left lung to both the left-sided vertical vein and the left atrium, associated with mild rheumatic mitral valve stenosis, in which the atrial septum was intact and the remaining venous system, including the coronary sinus, was otherwise normal (a variant of Lutembacher's syndrome). In order to abolish the left-to-right shunting, a transcatheter approach to close this venous structure was successfully attempted using an Amplatzer ASD Occluder device. The technical aspects and the alternative options of performing a procedure with a device for a purpose outside the scope of its approved label are discussed.

  2. Quantitative description of the regional mechanics of the left atria by electroanatomical mapping

    International Nuclear Information System (INIS)

    Kuklik, Pawel; Molaee, Payman; Brooks, Anthony G; John, Bobby; Worthley, Stephen G; Sanders, Prashanthan

    2010-01-01

    The left atrium is a complex chamber, which plays an integral role in the maintenance of physiologic hemodynamic and electrical stability of the heart and is involved in many disease states, most commonly atrial fibrillation. Preserving regions of the left atrium that contribute the greatest to atrial mechanical function during curative strategies for atrial fibrillation are important. We present here a new application of the CARTO electroanatomical mapping system in the assessment of the left atria mechanical function. Electroanatomical data were collected in course of the electrophysiological procedure in 11 control patients and 12 patients with paroxysmal atrial fibrillation. The three-dimensional geometry of the left atria was reconstructed in 10 ms intervals and segmented into distinct regions. For each segment, a regional ejection fraction was calculated. We found that anterior, septal and lateral segments have significantly greater regional ejection fraction than atria roof, inferior and posterior segments. Therefore, we hypothesize that in order to minimize the impact on atrial mechanical function, an important determinant of thromboembolic risk, damage should be minimized to these atrial regions

  3. Visitors׳ perceptions on the important factors of atrium design in shopping centers: A study of Gandaria City Mall and Ciputra World in Indonesia

    OpenAIRE

    Astrid Kusumowidagdo; Agus Sachari; Pribadi Widodo

    2016-01-01

    Atriums as quasi-internal public spaces in shopping centers play an essential role as an identity provider and offer spatial orientation in shopping center architecture. This study aims to examine the significant factors of atrium design, which can provide a sense of place for shopping center visitors. The research was conducted with the sequential exploratory method, which involved a qualitative study, followed by a quantitative study. The objects of this research were two shopping centers l...

  4. Effect of reactive agent and transesterification catalyst on properties of PLA/PBAT blends

    International Nuclear Information System (INIS)

    Pitivut, S; Suttiruengwong, S; Seadan, M

    2015-01-01

    This research aimed to study the properties of poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends with two different reactive systems: free radical reaction through peroxide (Perkadox) and transesterification catalyst (tetrabutyl titanate; TBT). Two blends composed of PLA as a matrix phase with the composition of 80 and 70 percent by weight. PLA/PBAT blends with Perkadox were prepared in twin screw extruder, whereas PLA/PBAT blends with TBT were prepared in an internal mixer. The morphology of the blends was investigated by scanning electron microscope (SEM). Tensile and impact testingsof the blends were reported. In case of the blends with Perkadox, SEM micrographs revealed that the size of particles was substantially reduced when adding more Perkadox. Young's modulus and the tensile strength of all blend ratios were insignificantly changed, whereas the elongation at break was decreased when compared to non-reactive blends due to the possible crosslinking reaction as observed from melt flow index (MFI) values. When adding Perkadox, the impact strength of PLA/PBAT (80/20) remained almost unchanged. However, the impact strength of PLA/PBAT (70/30) was enhanced, increasing to 110% for 0.05 phr Perkadox. In case of the blends with TBT, SEM micrographs showed the decrease in the particle size of PBAT phase when adding TBT. Young's modulus and the tensile strength of all blend ratios were not different, but the elongation at break was improved when adding TBT owing to the transesterification reaction. For PLA/PBAT (80/20), the elongation at break was increased by 39%, whereas the elongation at break was increased by 15% for PLA/PLA (70/30). The impact strength of all blend ratios unaffected. (paper)

  5. Inactivation of Peroxiredoxin 6 by the Pla Protease of Yersinia pestis.

    Science.gov (United States)

    Zimbler, Daniel L; Eddy, Justin L; Schroeder, Jay A; Lathem, Wyndham W

    2016-01-01

    Pneumonic plague represents the most severe form of disease caused by Yersinia pestis due to its ease of transmission, rapid progression, and high mortality rate. The Y. pestis outer membrane Pla protease is essential for the development of pneumonic plague; however, the complete repertoire of substrates cleaved by Pla in the lungs is not known. In this study, we describe a proteomic screen to identify host proteins contained within the bronchoalveolar lavage fluid of mice that are cleaved and/or processed by Y. pestis in a Pla-dependent manner. We identified peroxiredoxin 6 (Prdx6), a host factor that contributes to pulmonary surfactant metabolism and lung defense against oxidative stress, as a previously unknown substrate of Pla. Pla cleaves Prdx6 at three distinct sites, and these cleavages disrupt both the peroxidase and phospholipase A2 activities of Prdx6. In addition, we found that infection with wild-type Y. pestis reduces the abundance of extracellular Prdx6 in the lungs compared to that after infection with Δpla Y. pestis, suggesting that Pla cleaves Prdx6 in the pulmonary compartment. However, following infection with either wild-type or Δpla Y. pestis, Prdx6-deficient mice exhibit no differences in bacterial burden, host immune response, or lung damage from wild-type mice. Thus, while Pla is able to disrupt Prdx6 function in vitro and reduce Prdx6 levels in vivo, the cleavage of Prdx6 has little detectable impact on the progression or outcome of pneumonic plague. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Antioxidant migration resistance of SiOx layer in SiOx/PLA coated film.

    Science.gov (United States)

    Huang, Chongxing; Zhao, Yuan; Su, Hongxia; Bei, Ronghua

    2018-02-01

    As novel materials for food contact packaging, inorganic silicon oxide (SiO x ) films are high barrier property materials that have been developed rapidly and have attracted the attention of many manufacturers. For the safe use of SiO x films for food packaging it is vital to study the interaction between SiO x layers and food contaminants, as well as the function of a SiO x barrier layer in antioxidant migration resistance. In this study, we deposited a SiO x layer on polylactic acid (PLA)-based films to prepare SiO x /PLA coated films by plasma-enhanced chemical vapour deposition. Additionally, we compared PLA-based films and SiO x /PLA coated films in terms of the migration of different antioxidants (e.g. t-butylhydroquinone [TBHQ], butylated hydroxyanisole [BHA], and butylated hydroxytoluene [BHT]) via specific migration experiments and then investigated the effects of a SiO x layer on antioxidant migration under different conditions. The results indicate that antioxidant migration from SiO x /PLA coated films is similar to that for PLA-based films: with increase of temperature, decrease of food simulant polarity, and increase of single-sided contact time, the antioxidant migration rate and amount in SiO x /PLA coated films increase. The SiO x barrier layer significantly reduced the amount of migration of antioxidants with small and similar molecular weights and similar physical and chemical properties, while the degree of migration blocking was not significantly different among the studied antioxidants. However, the migration was affected by temperature and food simulant. Depending on the food simulants considered, the migration amount in SiO x /PLA coated films was reduced compared with that in PLA-based films by 42-46%, 44-47%, and 44-46% for TBHQ, BHA, and BHT, respectively.

  7. Plant Extract Synthesized PLA Nanoparticles for Controlled and Sustained Release of Quercetin: A Green Approach

    Science.gov (United States)

    Yadav, Sudesh Kumar

    2012-01-01

    Background Green synthesis of metallic nanoparticles (NPs) has been extensively carried out by using plant extracts (PEs) which have property of stabilizers/ emulsifiers. To our knowledge, there is no comprehensive study on applying a green approach using PEs for fabrication of biodegradable PLA NPs. Conventional methods rely on molecules like polyvinyl alcohol, polyethylene glycol, D-alpha-tocopheryl poly(ethylene glycol 1000) succinate as stabilizers/emulsifiers for the synthesis of such biodegradable NPs which are known to be toxic. So, there is urgent need to look for stabilizers which are biogenic and non-toxic. The present study investigated use of PEs as stabilizers/emulsifiers for the fabrication of stable PLA NPs. Synthesized PLA NPs through this green process were explored for controlled release of the well known antioxidant molecule quercetin. Methodology/Principal Findings Stable PLA NPs were synthesized using leaf extracts of medicinally important plants like Syzygium cumini (1), Bauhinia variegata (2), Cedrus deodara (3), Lonicera japonica (4) and Eleaocarpus sphaericus (5). Small and uniformly distributed NPs in the size range 70±30 nm to 143±36 nm were formed with these PEs. To explore such NPs for drugs/ small molecules delivery, we have successfully encapsulated quercetin a lipophilic molecule on a most uniformly distributed PLA-4 NPs synthesized using Lonicera japonica leaf extract. Quercetin loaded PLA-4 NPs were observed for slow and sustained release of quercetin molecule. Conclusions This green approach based on PEs mediated synthesis of stable PLA NPs pave the way for encapsulating drug/small molecules, nutraceuticals and other bioactive ingredients for safer cellular uptake, biodistribution and targeted delivery. Hence, such PEs synthesized PLA NPs would be useful to enhance the therapeutic efficacy of encapsulated small molecules/drugs. Furthermore, different types of plants can be explored for the synthesis of PLA as well as other

  8. Morphology and thermal properties of PLA films plasticized with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2015-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  9. Morphology and thermal properties of PLA films plasticised with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2013-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  10. Factors of Formation of Various Types of Left Ventricular Diastolic Filling in Adolescents with Myocardium Pathology

    Directory of Open Access Journals (Sweden)

    L.F. Bogmat

    2016-08-01

    Full Text Available Objective: to study the main components of the formation of impaired left ventricular diastolic filling in adolescents with myocardial pathology. Materials and methods. The study involved 110 adolescents with myocardial pathology aged 13–18 years, of which 40 — with heart rhythm disorder, 40 — with dysplastic cardiomyopathy, 30 — with primary hypertension. Morphological and functional parameters of the heart were studied using ultrasound according to standard procedure. Left ventricular diastolic function has been studied in the pulsed wave Doppler mode with transmitral flow mapping from the apical access of four-chambered heart. For an adequate assessment of left ventricular diastolic function and detection of its earliest disorders, adolescents underwent tests with isometric exercise. Based on these results, adolescents were divided in terms of the E/A ratio. In order to identify common latent factors that explain the correlation between indicators, we have used the factor analysis, namely, the principal component analysis. All statistical procedures were performed using application packages Statgraphics Centurion. Results. On the initial stages of formation of diastolic dysfunction of the left ventricular myocardium in adolescents, a significant role is played by a number of factors, which can be conditionally defined as the geometric, functional and neurohumoral factors consistently included in the pathological process. Thus, during the formation of left ventricular diastolic dysfunction type 1, the number one is neurohumoral factor, namely, the activation of the sympathoadrenal system, then peripheral vascular tone is being involved in the pathological process, and, consequently, a geometric factor — changing the sizes of the left atrium. In the formation of left ventricular diastolic dysfunction type 2, the process consistently involves the renin-angiotensin system, namely, renin, a functional factor is presented by the indices

  11. Optimization in obtaining PLA nanofibers/nHAP for pharmaceuticals release; Otimizacao na obtencao de nanofibras de PLA/nHAP para liberacao de farmacos

    Energy Technology Data Exchange (ETDEWEB)

    Becaro, A.A.; Paris, E.C.; Mattoso, L.H.C., E-mail: elaine.paris@embrapa.br [EMBRAPA Instrumentacao, Sao Carlos, SP (Brazil); Sciena, C.R.; Malafatti, J.D. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2016-07-01

    Hydroxyapatite (HAP) belongs to the family of calcium apatites. In nanometric form (nHAP) can be used as a drug carrier. The objective was to improve PLA nanofibers with nHAP insert for use in drug delivery. nHAP were obtained by coprecipitation method and characterized by XRD and TEM techniques. PLA fibers (10%) and 5% nHAP were obtained at a distance of 6 cm and flow rate of 0.1, 0.3 and 0.5 ml h{sup -1}, and characterized by SEM. The nHAP were single phase with rod shape, rounded tip and from 10 to 20 nm in diameter. The fibers obtained from pure PLA had to be more porous than in the presence of HAP. The diameters ranged from 0.2 to 2.4 micrometers. Among the fibers obtained that showed the best result was to flow 0.3 ml h{sup -1}. (author)

  12. The "People" in the PLA: Recruitment, Training, and Education in China's 80-Year-Old Military

    National Research Council Canada - National Science Library

    Liang, Justin B; Snyder, Sarah K

    2007-01-01

    ...: Recruitment, Training, and Education in China's 80-Year-Old Military." The 2007 PLA Conference, conducted by The National Bureau of Asian Research and the Strategic Studies Institute of the U.S...

  13. Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

    Energy Technology Data Exchange (ETDEWEB)

    Hemvichian, K.; Suwanmala, P. [Thailand Institute of Nuclear Technology (TINT) (Thailand); Kungsumrith, W. [Department of Industrial Engineering, Faculty of Engineering, Thammasat University (TU) (Thailand); Pongprayoon, T. [Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok (KMUTNB), Bangkok (Thailand)

    2011-07-01

    This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)

  14. Effect of ionizing radiation on the properties of PLA packaging materials

    International Nuclear Information System (INIS)

    Melski, K.; Kubera, H.; Gluszewski, W.; Zimek, Z.

    2011-01-01

    Poly(lactic acid) (PLA) is attractive as a substitute for classical polymer packaging material due to its biodegradability and sufficient mechanical and barrier properties. Presented research was focused on the changes of basic mechanical parameters after ionizing irradiation performed with doses in the range of 2.5-25 kGy, commonly used in radiation sterilization and preservation of foods. Two commercial available PLA packaging films were tested. The influence of radiation dose on the mechanical properties - tensile strength and elongation were determined using standardized methods. Radiation resistance of PLA is sufficient for packaging applications. The investigations of gas products of radiolysis of PLA have been made by gas chromatography after electron beam (EB) irradiations. (authors)

  15. Transparent films based on PLA and montmorillonite with tunable oxygen barrier properties

    DEFF Research Database (Denmark)

    Svagan, Anna; Åkesson, Anna; Cárdenas, Marité

    2012-01-01

    Polylactide (PLA) is viewed as a potential material to replace synthetic plastics (e.g., poly(ethylene terephthalate) (PET)) in food packaging, and there have been a number of developments in this direction. However, for PLA to be competitive in more demanding uses such as the packaging of oxygen......-sensitive foods, the oxygen permeability coefficient (OP) needs to be reduced by a factor of ∼10. To achieve this, a layer-by-layer (Lbl) approach was used to assemble alternating layers of montmorillonite clay and chitosan on extruded PLA film surfaces. When 70 bilayers were applied, the OP was reduced by 99...... and 96%, respectively, at 20 and 50% RH. These are, to our knowledge, the best improvements in oxygen barrier properties ever reported for a PLA/clay-based film. The process of assembling such multilayer structures was characterized using a quartz crystal microbalance with dissipation monitoring...

  16. In vitro and in vivo tests of PLA/d-HAp nanocomposite

    Science.gov (United States)

    Thom Nguyen, Thi; Hoang, Thai; Mao Can, Van; Son Ho, Anh; Hai Nguyen, Song; Thu Trang Nguyen, Thi; Pham, Thi Nam; Phuong Nguyen, Thu; Le Hien Nguyen, Thi; Thanh Dinh Thi, Mai

    2017-12-01

    The bioactivity of the PLA/d-HAp nanocomposite with 30 wt.% d-HAp was evaluated by in vitro tests and indicated that after 7 immersion days in SBF solution, PLA amorphous part was hydrolyzed and PLA crystal part was remained. The formation of apatite on the surface of the material was observed. The in vivo test results of PLA/d-HAp nanocomposite (70/30 wt/wt) on femur of dogs displayed that 3 months after grafting, the materials did not induce any osteitis, osteomyelitis or structural abnormalities. The histological and x-ray image demonstrated a growth of the bone into the material area, while osteitis and osteomyelitis were not observed.

  17. Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

    International Nuclear Information System (INIS)

    Hemvichian, K.; Suwanmala, P.; Kungsumrith, W.; Pongprayoon, T.

    2011-01-01

    This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)

  18. Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch

    CSIR Research Space (South Africa)

    Wokadala, OC

    2014-06-01

    Full Text Available In this study, waxy and high amylose starches were modified through butyl-etherification to facilitatecompatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magneticresonance spectroscopy and wettability tests...

  19. Impact du polylactide (PLA) sur la qualité des bioproduits au contact

    OpenAIRE

    Salazar Gonzalez , Romulo Vinicio

    2013-01-01

    Packaging plays a major role in the preservation of food but mass transfer between the packaging material and foodstuff occurs during shelf life leading to the quality deterioration. Polylactide (PLA) is a novel packaging material; therefore its interaction with food was investigated at service conditions. The sorption of ethyl esters, benzaldehyde and 2-nonanone at low concentrations and in mixture and the effects on the thermal properties of PLA were studied. Multiple Headspace Extraction (...

  20. China’s Military Modernization; An Analysis of the PLA Improved Logistic Capability

    Science.gov (United States)

    2013-02-14

    PLA headquarters, NDMC’s organize civilian personnel, trucks, ships, and other material required to support PLA operations. Joint logistics has...December 9, 2012. http://www.wantchinatimes.com/news-subclass- cnt.aspx?id=20120910000001&cid=1101 (accessed December 10, 2012). 27. Ibid., 28. KPMG ...34The role of transport and logistics in a changing economy," On the move in China. International Cooperative (“ KPMG International”), November 2011, 3

  1. Degradation of polylactic acid (Pla) at different doses of gamma radiation

    International Nuclear Information System (INIS)

    Castillo R, Y.

    2015-01-01

    The excessive use of polymers such as polyethylene (PET), polystyrene (Ps) and recently the polylactic acid (Pla) that take more than 20 years to degrade, have caused great pollution in the environment. In this study the effects of gamma radiation in the Pla to different doses were studied, in order to reduce the degradation time of this polymer. The changes in physico-chemical structure of Pla during radiation were studied by thermo-gravimetric/Mass analysis; differential scanning calorimetry; scanning electron microscopy; X-ray dispersive analysis; infrared spectroscopy; X-ray diffraction and mechanical tests of hardness, elasticity and deformation. With scanning electron microscopy, the morphology of the Pla surface unirradiated was observed, in which an apparently smooth surface was observed, after changes that had the Pla when irradiated also was observed, where the effects of radiation were observed in form of scratch, agglomeration and small fractures. By X-ray dispersive analysis was determined and verified the elemental chemical composition of the Pla; as expected the tests showed only carbon, oxygen and hydrogen. With thermo-gravimetric/Mass analysis the decomposition temperatures of Pla were determined, identifying that the degradation compounds are CO, CO 2 and CH 4 . With infrared spectrometry the major peaks of Pla were observed before and after being irradiated with increasing of radiation dose the intensity of the bands decreased. Also by X-ray diffraction was observed that the polymer is an amorphous material. The mechanical tests indicate that the values of each of the tests decrease significantly with increasing the radiation dose. (Author)

  2. Mechanical, thermal and morphological characterisation of 3D porous Pennisetum purpureum/PLA biocomposites scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Revati, R. [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Abdul Majid, M.S., E-mail: shukry@unimap.edu.my [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Ridzuan, M.J.M., E-mail: ridzuanjamir@unimap.edu.my [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Normahira, M., E-mail: normahira@unimap.edu.my [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Mohd Nasir, N.F., E-mail: nashrul@unimap.edu.my [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Rahman Y, M.N., E-mail: nurrahman@unimap.edu.my [School of Mechatronic Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis (Malaysia); Gibson, A.G., E-mail: geoff.gibson@ncl.ac.uk [School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2017-06-01

    The mechanical, thermal, and morphological properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) based scaffold were investigated. In this study, a scaffold containing P. purpureum and PLA was produced using the solvent casting and particulate leaching method. P. purpureum fibre, also locally known as Napier grass, is composed of 46% cellulose, 34% hemicellulose, and 20% lignin. PLA composites with various P. purpureum contents (10%, 20%, and 30%) were prepared and subsequently characterised. The morphologies, structures and thermal behaviours of the prepared composite scaffolds were characterised using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The morphology was studied using FESEM; the scaffold possessed 70–200 μm-sized pores with a high level of interconnectivity. The moisture content and mechanical properties of the developed porous scaffolds were further characterised. The P. purpureum/PLA scaffold had a greater porosity factor (99%) and compression modulus (5.25 MPa) than those of the pure PLA scaffold (1.73 MPa). From the results, it can be concluded that the properties of the highly porous P. purpureum/PLA scaffold developed in this study can be controlled and optimised. This can be used to facilitate the construction of implantable tissue-engineered cartilage. - Highlights: • High interconnected pores with 99% of porosity were observed for the scaffolds. • The pore sizes of the P. purpureum/PLA scaffolds ranged from 69 to 215 μm. • Addition of fillers improves the thermal properties and stability of the scaffolds. • PLA-PP{sub 30} scaffold showed enhanced compression modulus from 1.73 to 5.25 MPa.

  3. Molecular Cloning and Pharmacological Properties of an Acidic PLA2 from Bothrops pauloensis Snake Venom

    Directory of Open Access Journals (Sweden)

    Francis Barbosa Ferreira

    2013-12-01

    Full Text Available In this work, we describe the molecular cloning and pharmacological properties of an acidic phospholipase A2 (PLA2 isolated from Bothrops pauloensis snake venom. This enzyme, denominated BpPLA2-TXI, was purified by four chromatographic steps and represents 2.4% of the total snake venom protein content. BpPLA2-TXI is a monomeric protein with a molecular mass of 13.6 kDa, as demonstrated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF analysis and its theoretical isoelectric point was 4.98. BpPLA2-TXI was catalytically active and showed some pharmacological effects such as inhibition of platelet aggregation induced by collagen or ADP and also induced edema and myotoxicity. BpPLA2-TXI displayed low cytotoxicity on TG-180 (CCRF S 180 II and Ovarian Carcinoma (OVCAR-3, whereas no cytotoxicity was found in regard to MEF (Mouse Embryonic Fibroblast and Sarcoma 180 (TIB-66. The N-terminal sequence of forty-eight amino acid residues was determined by Edman degradation. In addition, the complete primary structure of 122 amino acids was deduced by cDNA from the total RNA of the venom gland using specific primers, and it was significantly similar to other acidic D49 PLA2s. The phylogenetic analyses showed that BpPLA2-TXI forms a group with other acidic D49 PLA2s from the gender Bothrops, which are characterized by a catalytic activity associated with anti-platelet effects.

  4. Molecular Cloning and Pharmacological Properties of an Acidic PLA2 from Bothrops pauloensis Snake Venom

    Science.gov (United States)

    Ferreira, Francis Barbosa; Gomes, Mário Sérgio Rocha; Naves de Souza, Dayane Lorena; Gimenes, Sarah Natalie Cirilo; Castanheira, Letícia Eulalio; Borges, Márcia Helena; Rodrigues, Renata Santos; Yoneyama, Kelly Aparecida Geraldo; Homsi Brandeburgo, Maria Inês; Rodrigues, Veridiana M.

    2013-01-01

    In this work, we describe the molecular cloning and pharmacological properties of an acidic phospholipase A2 (PLA2) isolated from Bothrops pauloensis snake venom. This enzyme, denominated BpPLA2-TXI, was purified by four chromatographic steps and represents 2.4% of the total snake venom protein content. BpPLA2-TXI is a monomeric protein with a molecular mass of 13.6 kDa, as demonstrated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) analysis and its theoretical isoelectric point was 4.98. BpPLA2-TXI was catalytically active and showed some pharmacological effects such as inhibition of platelet aggregation induced by collagen or ADP and also induced edema and myotoxicity. BpPLA2-TXI displayed low cytotoxicity on TG-180 (CCRF S 180 II) and Ovarian Carcinoma (OVCAR-3), whereas no cytotoxicity was found in regard to MEF (Mouse Embryonic Fibroblast) and Sarcoma 180 (TIB-66). The N-terminal sequence of forty-eight amino acid residues was determined by Edman degradation. In addition, the complete primary structure of 122 amino acids was deduced by cDNA from the total RNA of the venom gland using specific primers, and it was significantly similar to other acidic D49 PLA2s. The phylogenetic analyses showed that BpPLA2-TXI forms a group with other acidic D49 PLA2s from the gender Bothrops, which are characterized by a catalytic activity associated with anti-platelet effects. PMID:24304676

  5. PS-b-PMMA/PLA blends for nanoporous templates with hierarchical and tunable pore size

    Science.gov (United States)

    Nguyen, Thi-Hoa; Vayer, Marylène; Sinturel, Christophe

    2018-01-01

    Blends of poly(styrene)-block-poly(methyl methacrylate) (PS-b-PMMA) and poly(lactide) (PLA) were deposited in the form of thin films on the surface of modified silicon wafers and exposed to tetrahydrofuran (THF) vapor annealing. It was shown that in specific experimental conditions, a core-shell morphology consisting in cylinders with a PMMA shell and a PLA core, within a continuous matrix of PS, was formed. In this case, PLA naturally segregated in the core of the PMMA cylinders, minimizing the PS/PLA interaction, which constitutes the most incompatible pair (the interaction strength between the various components was confirmed in thin films of the corresponding polymer blends). Compared to other block copolymer/homopolymer blends described in the literature, this system exhibits unexpected high increase of the characteristic lengths of the system (center-to-center distance and diameter). This was attributed to a partial solubilization of the PLA in the PMMA corona (the two polymers are highly compatible), inducing an enhanced level of PS and PLA stretching caused by the strong repulsion between these two polymers. The selective extraction of the PLA yielded to porous domains with small dimensions (6 ± 2.5 nm), reaching the performances that are currently attained in highly incompatible block polymers with low molecular weight. Further PMMA removal revealed a second porosity level, with higher pores diameter and center-to-center distance compared to the neat PS-b-PMMA system. This work highlights how PS-b-PMMA, that currently represents one of the industrial standards nanoporous template precursors, can be modified in an easy and costless approach using PLA homopolymer addition.

  6. Mechanical, thermal and morphological characterisation of 3D porous Pennisetum purpureum/PLA biocomposites scaffold

    International Nuclear Information System (INIS)

    Revati, R.; Abdul Majid, M.S.; Ridzuan, M.J.M.; Normahira, M.; Mohd Nasir, N.F.; Rahman Y, M.N.; Gibson, A.G.

    2017-01-01

    The mechanical, thermal, and morphological properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) based scaffold were investigated. In this study, a scaffold containing P. purpureum and PLA was produced using the solvent casting and particulate leaching method. P. purpureum fibre, also locally known as Napier grass, is composed of 46% cellulose, 34% hemicellulose, and 20% lignin. PLA composites with various P. purpureum contents (10%, 20%, and 30%) were prepared and subsequently characterised. The morphologies, structures and thermal behaviours of the prepared composite scaffolds were characterised using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The morphology was studied using FESEM; the scaffold possessed 70–200 μm-sized pores with a high level of interconnectivity. The moisture content and mechanical properties of the developed porous scaffolds were further characterised. The P. purpureum/PLA scaffold had a greater porosity factor (99%) and compression modulus (5.25 MPa) than those of the pure PLA scaffold (1.73 MPa). From the results, it can be concluded that the properties of the highly porous P. purpureum/PLA scaffold developed in this study can be controlled and optimised. This can be used to facilitate the construction of implantable tissue-engineered cartilage. - Highlights: • High interconnected pores with 99% of porosity were observed for the scaffolds. • The pore sizes of the P. purpureum/PLA scaffolds ranged from 69 to 215 μm. • Addition of fillers improves the thermal properties and stability of the scaffolds. • PLA-PP 30 scaffold showed enhanced compression modulus from 1.73 to 5.25 MPa.

  7. The standard aqueous stem bark extract of Mangifera indica L. inhibits toxic PLA2 - NN-XIb-PLA2 of Indian cobra venom.

    Science.gov (United States)

    Dhananjaya, Bhadrapura Lakkappa; Sudarshan, Shivalingaiah; Dongol, Yashad; More, Sunil S

    2016-05-01

    The aqueous extract of Mangifera indica is known to possess diverse medicinal properties, which also includes anti-snake venom activities. However, its inhibitory potency and mechanism of action on multi-toxic snake venom phospholipases A2s are still unknown. Therefore, the objective of this study was to evaluate the modulatory effect of standard aqueous bark extract of M. indica on NN-XIb-PLA2 of Indian cobra venom. The in vitro sPLA2, in situ hemolytic and in vivo edema inhibition effect were carried out as described. Also the effect of substrate and calcium concentration was carried out. M. indica extract dose dependently inhibited the GIA sPLA2 (NN-XIb-PLA2) activity with an IC50 value of 7.6 μg/ml. M. indica extract effectively inhibited the indirect hemolytic activity up to 98% at ∼40 μg/ml concentration. Further, M. indica extract (0-50 μg/ml) inhibited the edema formed in a dose dependent manner. When examined as a function of increased substrate and calcium concentration, there was no relieve of inhibitory effect of M. indica extract on the NN-XIb-PLA2. Further, the inhibition was irreversible as evident from binding studies. The in vitro inhibition is well correlated with in situ and in vivo edema inhibiting activities of M. indica. As the inhibition is independent of substrate and calcium and was irreversible, it can be concluded that M. indica extract mode of inhibition could be due to direct interaction of components present in the extract with the PLA2 enzyme. The aqueous extract of M. indica effectively inhibits svPLA2 enzymatic and its associated toxic activities, which substantiate their anti-snake venom properties. Further in-depth studies on the role and mechanism of the principal constituents present in the extract, responsible for the anti-PLA2 activity will be interesting to develop them into potent antisnake component and also as an anti-inflammatory agent.

  8. PLA and two components silicon rubber blends aiming for frozen foods packaging applications

    Directory of Open Access Journals (Sweden)

    Utai Meekum

    2018-03-01

    Full Text Available Designing of PLA and two components silicone rubber blends was studies. Frozen food packaging application is the main ultimate aim. The statistical method using 23 DOE was conducted. The standard testing methods, in particular impact testing at sub-zero temperature, were performed. The preliminary blend formula comprised 1.0 phr of silane and polyester polyols, respectively, was initially resolved. Then, the optimize the silicone portion in the blends was determined. Blending formula using 8.0 phr of silicone with respect to PLA matrix gave rise to the overall satisfactory properties. 3. TETA was used as the silicone curing agent and reactively blended onto the ingredients. TETA at 0.4 phr, with respect to the silicone, enhanced the mechanical properties, especially flexibility and toughness, of the PLA/silicone blend. Exceeding the optimal TETA loading would cause the chain scission and also the dilution effects. Hence, marginal inferior properties of the blends were be experienced. The preliminary biodegradability investigation found that the PLA/silicone blend initially triggered at the second week. Its degradation rate was likely to be faster than neat PLA. Keywords: PLA/silicone blends, Mechanical properties, Sub-zero impact strength

  9. Swelling kinetics and impregnation of PLA with thymol under supercritical CO2 conditions

    Directory of Open Access Journals (Sweden)

    Milovanović Stoja L.

    2016-01-01

    Full Text Available The present work was aimed to study swelling kinetics of polylactic acid (PLA and its impregnation with thymol in supercritical carbon dioxide (scCO2 medium. The influences of temperature and soaking time on the swelling kinetics and impregnation yield of PLA cylindrical disc and film were investigated. Swelling experiments were performed in a high pressure view cell at 10 MPa and temperatures of 40°C, 60°C and 75°C for 2 to 24 h. On the basis of swelling kinetics, pressure of 10 MPa and temperature of 40°C were chosen for supercritical solvent impregnation (SSI of the PLA samples during 2 to24 h. The highest swelling extent was observed for the PLA monolith after 24 h treatment with pure scCO2 (7.5% and scCO2 with thymol (118.3%. It was shown that sufficiently high amount of thymol can be loaded into both PLA monolith and film using SSI after only 2 h (10.0% and 6.6%, respectively. Monolith and film of PLA impregnated with thymol could be suitable for active food packaging and sterile medical disposables.

  10. Improving the engineering properties of PLA for 3D printing and beyond

    Science.gov (United States)

    Rocha Gutierrez, Carmen Raquel

    Additive manufacturing (AM), now more commonly known as 3D printing, has been classified as efficient, fast, and practical in the prototyping sector of product development. In the work presented here, we will use one of the AM techniques known as Material extrusion 3D printing (ME3DP), which has all the advantages of AM. However, one of the biggest challenges facing ME3DP technologies is the limitation of the range of materials used by this technique. Acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA) are currently the most common thermoplastics materials used in ME3DP because of their ability to melt and be reprocessed. PLA is a biodegradable polymer derived from renewable sources such as corn, and sugarcane. The expanded use of this polymer over traditional petroleum-based plastics (ABS) will decrease the demand on petrochemicals, and also lead to less non-biodegradable polymeric waste. While PLA offers an eco-friendly solution for polymeric 3D printing, the mechanical performance is limited by PLA's inherent characteristics (such as moisture absorbance) that may degrade the plastic during processing. PLA novel systems were used through this research maintaining the compatibility with material extrusion 3D printers. The purpose of this investigation is to alter the physical properties of PLA with sustainable additives in order to improve the end use products from this material.

  11. Polybiguanide (PHMB) loaded in PLA scaffolds displaying high hydrophobic, biocompatibility and antibacterial properties

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, Elena; Calderón, Silvia [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Valle, Luis J. del, E-mail: luis.javier.del.valle@upc.edu [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, Jordi [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CrNE), Universitat Politècnica de Catalunya, Edifici C, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain)

    2015-05-01

    Polyhexamethylenebiguanide hydrochloride (PHMB), a low molecular weight polymer related to chlorohexidine (CHX), is a well-known antibacterial agent. In this study, polylactide (PLA) nanofibers loaded with PHMB were produced by electrospinning to obtain 3D biodegradable scaffolds with antibacterial properties. PLA fibers loaded with CHX were used as control. The electrospun fibers were studied and analyzed by SEM, FTIR, DSC and contact angle measurements. PHMB and CHX release from loaded scaffolds was evaluated, as well as their antibacterial activity and biocompatibility. The results showed that the nanofibers became smoother and their diameter smaller with increasing the amount of loaded PHMB. This feature led to an increase of both surface roughness and hydrophobicity of the scaffold. PHMB release was highly dependent on the hydrophilicity of the medium and differed from that determined for CHX. Lastly, PHMB-loaded PLA scaffolds showed antibacterial properties since they inhibited adhesion and bacterial growth, and exhibited biocompatible characteristics for the adhesion and proliferation of both fibroblast and epithelial cell lines. - Highlights: • Nanofibers of PLA-PHMB (antibacterial polymer) were prepared by electrospinning. • PHMB has hydrophilic character but the PLA-PHMB scaffolds were highly hydrophobic. • The high-hydrophobicity of the new scaffolds conditioned the release of PHMB. • The controlled release of PHMB inhibited the growth and bacterial adhesion. • PLA-PHMB scaffolds have biocompatibility with fibroblast and epithelial cells.

  12. Fine Mapping and Cloning of Leafy Head Mutant Gene pla1-5 in Rice

    Directory of Open Access Journals (Sweden)

    Gong-neng FENG

    2013-09-01

    Full Text Available We identified a leafy head mutant pla1-5 (plastochron 1-5 from the progeny of japonica rice cultivar Taipei 309 treated with 60Co-γ ray irradiation. The pla1-5 mutant has a dwarf phenotype and small leaves. Compared with its wild type, pla1-5 has more leaves and fewer tillers, and it fails to produce normal panicles at the maturity stage. Genetic analysis showed that the pla1-5 phenotype is controlled by a single recessive nuclear gene. Using the map-based cloning strategy, we narrowed down the location of the target gene to a 58-kb region between simple sequence repeat markers CHR1027 and CHR1030 on the long arm of chromosome 10. The target gene cosegregated with molecular markers CHR1028 and CHR1029. There were five predicted genes in the mapped region. The results from sequencing analysis revealed that there was one base deletion in the first exon of LOC_Os10g26340 encoding cytochrome P450 CYP78A11 in the pla1-5 mutant, which might result in a downstream frame shift and premature termination. These results suggest that the P450 CYP78A11 gene is the candidate gene of PLA1-5.

  13. Molecular Weight and Structural Properties of Biodegradable PLA Synthesized with Different Catalysts by Direct Melt Polycondensation

    Directory of Open Access Journals (Sweden)

    Hyung Woo Lee

    2015-09-01

    Full Text Available Production of biodegradable polylactic acid (PLA from biomassbased lactic acid is widely studied for substituting petro-based plastics or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst, γ-aluminium(III oxide (γ-Al2O3 or zinc oxide (ZnO, in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for γ-Al2O3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol than that from γ-Al2O3 (81,400 g/mol. The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1, whereas the PLA produced by two other polymerization methods – polycondensation and ring opening polymerization –showed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as –OH vibration peak and at 1,750 cm-1 as –C=O carbonyl vibrational peak.

  14. Multifunctional PLA-PHB/cellulose nanocrystal films: processing, structural and thermal properties.

    Science.gov (United States)

    Arrieta, M P; Fortunati, E; Dominici, F; Rayón, E; López, J; Kenny, J M

    2014-07-17

    Cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose by acid hydrolysis were added into poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends to improve the final properties of the multifunctional systems. CNC were also modified with a surfactant (CNCs) to increase the interfacial adhesion in the systems maintaining the thermal stability. Firstly, masterbatch pellets were obtained for each formulation to improve the dispersion of the cellulose structures in the PLA-PHB and then nanocomposite films were processed. The thermal stability as well as the morphological and structural properties of nanocomposites was investigated. While PHB increased the PLA crystallinity due to its nucleation effect, well dispersed CNC and CNCs not only increased the crystallinity but also improved the processability, the thermal stability and the interaction between both polymers especially in the case of the modified CNCs based PLA-PHB formulation. Likewise, CNCs were better dispersed in PLA-CNCs and PLA-PHB-CNCs, than CNC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Plasma Modification of Poly Lactic Acid Solutions to Generate High Quality Electrospun PLA Nanofibers.

    Science.gov (United States)

    Rezaei, Fatemeh; Nikiforov, Anton; Morent, Rino; De Geyter, Nathalie

    2018-02-02

    Physical properties of pre-electrospinning polymer solutions play a key role in electrospinning as they strongly determine the morphology of the obtained electrospun nanofibers. In this work, an atmospheric-pressure argon plasma directly submerged in the liquid-phase was used to modify the physical properties of poly lactic acid (PLA) spinning solutions in an effort to improve their electrospinnability. The electrical characteristics of the plasma were investigated by two methods; V-I waveforms and Q-V Lissajous plots while the optical emission characteristics of the plasma were also determined using optical emission spectroscopy (OES). To perform a complete physical characterization of the plasma-modified polymer solutions, measurements of viscosity, surface tension, and electrical conductivity were performed for various PLA concentrations, plasma exposure times, gas flow rates, and applied voltages. Moreover, a fast intensified charge-couple device (ICCD) camera was used to image the bubble dynamics during the plasma treatments. In addition, morphological changes of PLA nanofibers generated from plasma-treated PLA solutions were observed by scanning electron microscopy (SEM). The performed plasma treatments were found to induce significant changes to the main physical properties of the PLA solutions, leading to an enhancement of electrospinnability and an improvement of PLA nanofiber formation.

  16. The Pla Protease of Yersinia pestis Degrades Fas Ligand to Manipulate Host Cell Death and Inflammation

    Science.gov (United States)

    Caulfield, Adam J.; Walker, Margaret E.; Gielda, Lindsay M.; Lathem, Wyndham W.

    2014-01-01

    SUMMARY Pneumonic plague is a deadly respiratory disease caused by Yersinia pestis. The bacterial protease Pla contributes to disease progression and manipulation of host immunity, but the mechanisms by which this occurs are largely unknown. Here we show that Pla degrades the apoptotic signaling molecule Fas ligand (FasL) to prevent host cell apoptosis and inflammation. Wild-type Y. pestis, but not a Pla mutant (Δpla), degrades FasL, which results in decreased downstream caspase-3/7 activation and reduced apoptosis. Similarly, lungs of mice challenged with wild-type Y. pestis show reduced levels of FasL and activated caspase-3/7 compared to Δpla infection. Consistent with a role for FasL in regulating immune responses, Δpla infection results in aberrant pro-inflammatory cytokine levels. The loss of FasL or inhibition of caspase activity alters host inflammatory responses and enables enhanced Y. pestis outgrowth in the lungs. Thus, by degrading FasL, Y. pestis manipulates host cell death pathways to facilitate infection. PMID:24721571

  17. Mechanical, thermal and morphological characterisation of 3D porous Pennisetum purpureum/PLA biocomposites scaffold.

    Science.gov (United States)

    Revati, R; Abdul Majid, M S; Ridzuan, M J M; Normahira, M; Mohd Nasir, N F; Rahman Y, M N; Gibson, A G

    2017-06-01

    The mechanical, thermal, and morphological properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) based scaffold were investigated. In this study, a scaffold containing P. purpureum and PLA was produced using the solvent casting and particulate leaching method. P. purpureum fibre, also locally known as Napier grass, is composed of 46% cellulose, 34% hemicellulose, and 20% lignin. PLA composites with various P. purpureum contents (10%, 20%, and 30%) were prepared and subsequently characterised. The morphologies, structures and thermal behaviours of the prepared composite scaffolds were characterised using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The morphology was studied using FESEM; the scaffold possessed 70-200μm-sized pores with a high level of interconnectivity. The moisture content and mechanical properties of the developed porous scaffolds were further characterised. The P. purpureum/PLA scaffold had a greater porosity factor (99%) and compression modulus (5.25MPa) than those of the pure PLA scaffold (1.73MPa). From the results, it can be concluded that the properties of the highly porous P. purpureum/PLA scaffold developed in this study can be controlled and optimised. This can be used to facilitate the construction of implantable tissue-engineered cartilage. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Shape memory polymer hybrids of SBS/dl-PLA and their shape memory effects

    International Nuclear Information System (INIS)

    Zhang, Heng; Chen, Zhi; Zheng, Zheng; Zhu, Xiaomin; Wang, Haitao

    2013-01-01

    The hybrids of styrene-butadiene-styrene tri-block copolymer (SBS) and amorphous poly(dl-lactic acid) (dl-PLA) are found to exhibit shape memory effects, which gives an example of a dual-domain shape memory system consisting of an elastic domain and a thermo-switch domain. The dual-domain manner in this hybrid is studied by means of differential scanning calorimetry (DSC) and scanning electron microscope (SEM). Subsequently, the tensile test clarifies the interactions of the two domains on shape memory effects. As an elastic domain, SBS offers good shape recovery when its content exceeds 50 wt%. As a thermo-switch domain, dl-PLA triggers the shape memory effect at ca. 55 °C and offers good shape fixing when the content exceeds 30 wt%. An easy-to-do and easy-to-know feature of the hybrid is that the optimization of shape memory effect can be achieved by generating bicontinous phases of SBS and dl-PLA, in which the dl-PLA content ranges from 30 to 70 wt%. -- Highlights: ► The composite materials of SBS and amorphous dl-PLA were prepared by blending. ► A continuous domain was observed with the increasing content of dl-PLA. ► The composites exhibited shape memory effects.

  19. Electro-spun PLA-PEG-yarns for tissue engineering applications.

    Science.gov (United States)

    Kruse, Magnus; Greuel, Marc; Kreimendahl, Franziska; Schneiders, Thomas; Bauer, Benedict; Gries, Thomas; Jockenhoevel, Stefan

    2018-06-27

    Electro-spinning is widely used in tissue-engineered applications mostly in form of non-woven structures. The development of e-spun yarn opens the door for textile fabrics which combine the micro to nanoscale dimension of electro-spun filaments with three-dimensional (3D) drapable textile fabrics. Therefore, the aim of the study was the implementation of a process for electro-spun yarns. Polylactic acid (PLA) and polyethylene glycol (PEG) were spun from chloroform solutions with varying PLA/PEG ratios (100:0, 90:10, 75:25 and 50:50). The yarn samples produced were analyzed regarding their morphology, tensile strength, water uptake and cytocompatibility. It was found that the yarn diameter decreased when the funnel collector rotation was increasd, however, the fiber diameter was not influenced. The tensile strength was also found to be dependent on the PEG content. While samples composed of 100% PLA showed a tensile strength of 2.5±0.7 cN/tex, the tensile strength increased with a decreasing PLA content (PLA 75%/PEG 25%) to 6.2±0.5 cN/tex. The variation of the PEG content also influenced the viscosity of the spinning solutions. The investigation of the cytocompatibility with endothelial cells was conducted for PLA/PEG 90:10 and 75:25 and indicated that the samples are cytocompatible.

  20. Polybiguanide (PHMB) loaded in PLA scaffolds displaying high hydrophobic, biocompatibility and antibacterial properties

    International Nuclear Information System (INIS)

    Llorens, Elena; Calderón, Silvia; Valle, Luis J. del; Puiggalí, Jordi

    2015-01-01

    Polyhexamethylenebiguanide hydrochloride (PHMB), a low molecular weight polymer related to chlorohexidine (CHX), is a well-known antibacterial agent. In this study, polylactide (PLA) nanofibers loaded with PHMB were produced by electrospinning to obtain 3D biodegradable scaffolds with antibacterial properties. PLA fibers loaded with CHX were used as control. The electrospun fibers were studied and analyzed by SEM, FTIR, DSC and contact angle measurements. PHMB and CHX release from loaded scaffolds was evaluated, as well as their antibacterial activity and biocompatibility. The results showed that the nanofibers became smoother and their diameter smaller with increasing the amount of loaded PHMB. This feature led to an increase of both surface roughness and hydrophobicity of the scaffold. PHMB release was highly dependent on the hydrophilicity of the medium and differed from that determined for CHX. Lastly, PHMB-loaded PLA scaffolds showed antibacterial properties since they inhibited adhesion and bacterial growth, and exhibited biocompatible characteristics for the adhesion and proliferation of both fibroblast and epithelial cell lines. - Highlights: • Nanofibers of PLA-PHMB (antibacterial polymer) were prepared by electrospinning. • PHMB has hydrophilic character but the PLA-PHMB scaffolds were highly hydrophobic. • The high-hydrophobicity of the new scaffolds conditioned the release of PHMB. • The controlled release of PHMB inhibited the growth and bacterial adhesion. • PLA-PHMB scaffolds have biocompatibility with fibroblast and epithelial cells

  1. The left atrio-vertebral ratio. A new simple means for assessing left atrial enlargement on computed tomography

    International Nuclear Information System (INIS)

    Montillet, Marie; Tasu, Jean-Pierre; Baque-Juston, Marie; Bertrand, Sandra; Berthier, Frederic; Zarqane, Naima; Brunner, Philippe

    2018-01-01

    The purpose of this study is to describe a new method to quickly estimate left atrial enlargement (LAE) on Computed Tomography. Left atrial (LA) volume was assessed with a 3D-threshold Hounsfield unit detection technique, including left atrial appendage and excluding pulmonary venous confluence, in 201 patients with ECG-gated 128-slice dual-source CT and indexed to body surface area. LA and vertebral axial diameter and area were measured at the bottom level of the right inferior pulmonary vein ostium. Ratio of LA diameter and surface on vertebra (LAVD and LAVA) were compared to LA volume. In accordance with the literature, a cutoff value of 78 ml/m 2 was chosen for maximal normal LA volume. 18% of LA was enlarged. The best cutoff values for LAE assessment were 2.5 for LAVD (AUC: 0.65; 95% CI: 0.58-0.73; sensitivity: 57%; specificity: 71%), and 3 for LAVA (AUC: 0.78; 95% CI: 0.72-0.84; sensitivity: 67%; specificity: 79%), with higher accuracy for LAVA (P=0.015). Inter-observer and intra-observer variability were either good or excellent for LAVD and LAVA (respective intraclass coefficients: 0.792 and 0.910; 0.912 and 0.937). A left atrium area superior to three times the vertebral area indicates LAE with high specificity. (orig.)

  2. The left atrio-vertebral ratio. A new simple means for assessing left atrial enlargement on computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Montillet, Marie; Tasu, Jean-Pierre [Centre Hospitalier Universitaire de Poitiers, Poitiers (France); Baque-Juston, Marie; Bertrand, Sandra; Berthier, Frederic; Zarqane, Naima; Brunner, Philippe [Hopital Princesse Grace, Monaco (Monaco)

    2018-03-15

    The purpose of this study is to describe a new method to quickly estimate left atrial enlargement (LAE) on Computed Tomography. Left atrial (LA) volume was assessed with a 3D-threshold Hounsfield unit detection technique, including left atrial appendage and excluding pulmonary venous confluence, in 201 patients with ECG-gated 128-slice dual-source CT and indexed to body surface area. LA and vertebral axial diameter and area were measured at the bottom level of the right inferior pulmonary vein ostium. Ratio of LA diameter and surface on vertebra (LAVD and LAVA) were compared to LA volume. In accordance with the literature, a cutoff value of 78 ml/m{sup 2} was chosen for maximal normal LA volume. 18% of LA was enlarged. The best cutoff values for LAE assessment were 2.5 for LAVD (AUC: 0.65; 95% CI: 0.58-0.73; sensitivity: 57%; specificity: 71%), and 3 for LAVA (AUC: 0.78; 95% CI: 0.72-0.84; sensitivity: 67%; specificity: 79%), with higher accuracy for LAVA (P=0.015). Inter-observer and intra-observer variability were either good or excellent for LAVD and LAVA (respective intraclass coefficients: 0.792 and 0.910; 0.912 and 0.937). A left atrium area superior to three times the vertebral area indicates LAE with high specificity. (orig.)

  3. Kinetics and mechanism of the biodegradation of PLA/clay nanocomposites during thermophilic phase of composting process.

    Science.gov (United States)

    Stloukal, Petr; Pekařová, Silvie; Kalendova, Alena; Mattausch, Hannelore; Laske, Stephan; Holzer, Clemens; Chitu, Livia; Bodner, Sabine; Maier, Guenther; Slouf, Miroslav; Koutny, Marek

    2015-08-01

    The degradation mechanism and kinetics of polylactic acid (PLA) nanocomposite films, containing various commercially available native or organo-modified montmorillonites (MMT) prepared by melt blending, were studied under composting conditions in thermophilic phase of process and during abiotic hydrolysis and compared to the pure polymer. Described first order kinetic models were applied on the data from individual experiments by using non-linear regression procedures to calculate parameters characterizing aerobic composting and abiotic hydrolysis, such as carbon mineralization, hydrolysis rate constants and the length of lag phase. The study showed that the addition of nanoclay enhanced the biodegradation of PLA nanocomposites under composting conditions, when compared with pure PLA, particularly by shortening the lag phase at the beginning of the process. Whereas the lag phase of pure PLA was observed within 27days, the onset of CO2 evolution for PLA with native MMT was detected after just 20days, and from 13 to 16days for PLA with organo-modified MMT. Similarly, the hydrolysis rate constants determined tended to be higher for PLA with organo-modified MMT, particularly for the sample PLA-10A with fastest degradation, in comparison with pure PLA. The acceleration of chain scission in PLA with nanoclays was confirmed by determining the resultant rate constants for the hydrolytical chain scission. The critical molecular weight for the hydrolysis of PLA was observed to be higher than the critical molecular weight for onset of PLA mineralization, suggesting that PLA chains must be further shortened so as to be assimilated by microorganisms. In conclusion, MMT fillers do not represent an obstacle to acceptance of the investigated materials in composting facilities. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. A Large Left Ventricle Myxoma: Presenting with Epigastric Pain and Weight Loss

    Directory of Open Access Journals (Sweden)

    Solmaz Fakhari

    2016-01-01

    Full Text Available Cardiac myxomas are the most common benign tumors found in the heart. They usually appear in the left atrium. Those originating from the left ventricle (LV are rare. Although clinical presentation may vary, dyspnea and embolism are the most commonly reported symptoms. In the present case study, a 27-year-old woman with a large myxoma originating from the left ventricular free wall is studied. She had atypical complaints, mainly epigastric discomfort, nausea, vomiting, and anorexia. She was hospitalized for acute abdomen, but subsequent investigations revealed a large myxoma that fully filled the LV and severely compromised the flow of the aortic and mitral valves. After successful emergency tumor resection, all symptoms disappeared. The uncommon presentation caused by these tumors is discussed in this study.

  5. Isolated persistent left superior vena cava: A case report and its clinical implications

    Directory of Open Access Journals (Sweden)

    Samarjit Bisoyi

    2017-01-01

    Full Text Available The venous anomaly of a persistent left superior vena cava (PLSVC affects 0.3%-0.5% of the general population. PLSVC with absent right superior vena cava, also termed as "isolated PLSVC," is an extremely rare venous anomaly. Almost half of the patients with isolated PLSVC have cardiac anomalies in the form of atrial septal defect, endocardial cushion defects, or tetralogy of Fallot. Isolated PLSVC is usually innocuous. Its discovery, however, has important clinical implications. It can pose clinical difficulties with central venous access, cardiothoracic surgeries, and pacemaker implantation. When it drains to the left atrium, it may create a right to left shunt. In this case report, we present the incidental finding of isolated PLSVC in a patient who underwent aortic valve replacement. Awareness about this condition and its variations is important to avoid complications.

  6. Types of Diastolic Dysfunction of the Left Ventricle in Adolescents with Myocardial Pathology

    Directory of Open Access Journals (Sweden)

    L.F. Bogmat

    2014-05-01

    Full Text Available In adolescents with myocardial pathology during isometric tests we detected three types of diastolic dysfunction of the left ventricle (LV of the heart, depending on E/A ratio. The most pronounced signs of diastolic filling disorders were detected in the third group of patients, as evidenced: by a tendency to increase isovolumic relaxation time, a significant increase of slowing down time of the first phase of left ventricular filling, reduced LV filling rate both in the first phase of the passive filling and the second phase of active LV filling, increasing E/A ratio of more than 2, significant dilation of the left atrium, as well as positive increase in diastolic reserve that confirms deeper diastolic dysfunction in these adolescents compared with other subgroups.

  7. Two Isoforms of Yersinia pestis Plasminogen Activator Pla: Intraspecies Distribution, Intrinsic Disorder Propensity, and Contribution to Virulence.

    Science.gov (United States)

    Dentovskaya, Svetlana V; Platonov, Mikhail E; Svetoch, Tat'yana E; Kopylov, Pavel Kh; Kombarova, Tat'yana I; Ivanov, Sergey A; Shaikhutdinova, Rima Z; Kolombet, Lyubov' V; Chauhan, Sadhana; Ablamunits, Vitaly G; Motin, Vladimir L; Uversky, Vladimir N; Anisimov, Andrey P

    2016-01-01

    It has been shown previously that several endemic Y. pestis isolates with limited virulence contained the I259 isoform of the outer membrane protease Pla, while the epidemic highly virulent strains possessed only the T259 Pla isoform. Our sequence analysis of the pla gene from 118 Y. pestis subsp. microtus strains revealed that the I259 isoform was present exclusively in the endemic strains providing a convictive evidence of more ancestral origin of this isoform. Analysis of the effects of the I259T polymorphism on the intrinsic disorder propensity of Pla revealed that the I259T mutation slightly increases the intrinsic disorder propensity of the C-terminal tail of Pla and makes this protein slightly more prone for disorder-based protein-protein interactions, suggesting that the T259 Pla could be functionally more active than the I259 Pla. This assumption was proven experimentally by assessing the coagulase and fibrinolytic activities of the two Pla isoforms in human plasma, as well as in a direct fluorometric assay with the Pla peptide substrate. The virulence testing of Pla-negative or expressing the I259 and T259 Pla isoforms Y. pestis subsp. microtus and subsp. pestis strains did not reveal any significant difference in LD50 values and dose-dependent survival assays between them by using a subcutaneous route of challenge of mice and guinea pigs or intradermal challenge of mice. However, a significant decrease in time-to-death was observed in animals infected with the epidemic T259 Pla-producing strains as compared to the parent Pla-negative variants. Survival curves of the endemic I259 Pla+ strains fit between them, but significant difference in mean time to death post infection between the Pla-strains and their I259 Pla+ variants could be seen only in the isogenic set of subsp. pestis strains. These findings suggest an essential role for the outer membrane protease Pla evolution in Y. pestis bubonic infection exacerbation that is necessary for intensification

  8. RhoA/Rho Kinase Mediates Neuronal Death Through Regulating cPLA2 Activation.

    Science.gov (United States)

    Wu, Xiangbing; Walker, Chandler L; Lu, Qingbo; Wu, Wei; Eddelman, Daniel B; Parish, Jonathan M; Xu, Xiao-Ming

    2017-11-01

    Activation of RhoA/Rho kinase leads to growth cone collapse and neurite retraction. Although RhoA/Rho kinase inhibition has been shown to improve axon regeneration, remyelination and functional recovery, its role in neuronal cell death remains unclear. To determine whether RhoA/Rho kinase played a role in neuronal death after injury, we investigated the relationship between RhoA/Rho kinase and cytosolic phospholipase A 2 (cPLA 2 ), a lipase that mediates inflammation and cell death, using an in vitro neuronal death model and an in vivo contusive spinal cord injury model performed at the 10th thoracic (T10) vertebral level. We found that co-administration of TNF-α and glutamate induced spinal neuron death, and activation of RhoA, Rho kinase and cPLA 2 . Inhibition of RhoA, Rho kinase and cPLA 2 significantly reduced TNF-α/glutamate-induced cell death by 33, 52 and 43 %, respectively (p < 0.001). Inhibition of RhoA and Rho kinase also significantly downregulated cPLA 2 activation by 66 and 60 %, respectively (p < 0.01). Furthermore, inhibition of RhoA and Rho kinase reduced the release of arachidonic acid, a downstream substrate of cPLA 2 . The immunofluorescence staining showed that ROCK 1 or ROCK 2 , two isoforms of Rho kinase, was co-localized with cPLA 2 in neuronal cytoplasm. Interestingly, co-immunoprecipitation (Co-IP) assay showed that ROCK 1 or ROCK 2 bonded directly with cPLA 2 and phospho-cPLA 2 . When the Rho kinase inhibitor Y27632 was applied in mice with T10 contusion injury, it significantly decreased cPLA 2 activation and expression and reduced injury-induced apoptosis at and close to the lesion site. Taken together, our results reveal a novel mechanism of RhoA/Rho kinase-mediated neuronal death through regulating cPLA 2 activation.

  9. Primary Leiomyosarcoma in the Inferior Vena Cava Extended to the Right Atrium: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Shuichi Fujita

    2016-10-01

    Full Text Available A 38-year-old woman had developed an abdominal distention, lower extremity edema, and dyspnea. Imaging examination revealed a large mass in the right atrium which was connected to lesions within the inferior vena cava. Although complete resection of the mass was not possible, partial surgical tumor resection was performed to avoid pulmonary embolization and circulatory collapse. Leiomyosarcoma was diagnosed histologically, and chemotherapy (doxorubicin followed by radiotherapy was started. By reviewing papers published in the past 10 years that included 322 patients, we also discuss the clinical presentations and prognosis of leiomyosarcoma in the inferior vena cava.

  10. Bark polyflavonoids from Pinus radiata as functional building-blocks for polylactic acid (PLA-based green composites

    Directory of Open Access Journals (Sweden)

    D. E. Garcia

    2016-10-01

    Full Text Available Polylactic acid (PLA was melt-blended with Pinus radiata unmodified and modified (hydroxypropyled bark polyflavonoids in order to use such polyphenolic building-blocks as functional additives for envisaged applications. Rheological, morphological, molecular, thermal, and flexural properties were studied. Polyflavonoids improved blend processability in terms of short-time mixing. Furthermore, hydroxypropylated polyflavonoids improve miscibility in binary and ternary blends. Blend-composition affects crystallization-, melting-, and glass transition-temperature of PLA, as well as thermal resistance, and flexural properties of the blends. Polyflavonoids induced PLA-crystallization, and polymer-chain decomposition. Modified and unmodified bark polyflavonoids from radiata pine can be used successfully in PLA-based green composites beyond the food-packaging applications. The high compatibility between PLA and hydroxypropyled polyflavonoids highlights the potential of such phenolic derivatives for PLA-based material design.

  11. [Left atrial electric isolation in the treatment of atrial fibrillation secondary to rheumatic valvular disease].

    Science.gov (United States)

    Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

    1992-08-01

    Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent valve surgery. From May 1989 to September 1991, 62 patients underwent mitral valve surgery (Group I), 19 underwent mitral valve surgery and DeVega tricuspid annuloplasty (Group II), 15 underwent mitral and aortic surgery (Group III), and 4 patients underwent mitral and aortic surgery and DeVega tricuspid annuloplasty (Group IV). Left atrial isolation was performed prolonging the usual left paraseptal atriotomy towards the left fibrous trigone anteriorly, and the postero-medial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesion were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 cases (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (Group I: 80.7%; Group II: 68.5%; Group III 86.7%, Group IV 75% - p = N.S.). Three cases of late mortality (3.1%) were registered. long-term results showed persistence of SR in 71% of Group I, 61.2% of Group II, 85.8% of Group III, and 100% of Group IV. The unique risk factor for late recurrency of atrial fibrillation was found to be a duration of preoperative AF longer than 6 months. Due to the high success rate in recovering the sinus rhythm, we suggest left atrial isolation in patients with chronic atrial fibrillation undergoing valvular surgery.

  12. Bamboo–Polylactic Acid (PLA) Composite Material for Structural Applications

    Science.gov (United States)

    Pozo Morales, Angel; Güemes, Alfredo; Fernandez-Lopez, Antonio; Carcelen Valero, Veronica; De La Rosa Llano, Sonia

    2017-01-01

    Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long) were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA) matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at industrial sectors such

  13. Bamboo-Polylactic Acid (PLA) Composite Material for Structural Applications.

    Science.gov (United States)

    Pozo Morales, Angel; Güemes, Alfredo; Fernandez-Lopez, Antonio; Carcelen Valero, Veronica; De La Rosa Llano, Sonia

    2017-11-09

    Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long) were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA) matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at industrial sectors such

  14. Bamboo–Polylactic Acid (PLA Composite Material for Structural Applications

    Directory of Open Access Journals (Sweden)

    Angel Pozo Morales

    2017-11-01

    Full Text Available Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at

  15. Polylactic acid (PLA)/Silver-NP/VitaminE bionanocomposite electrospun nanofibers with antibacterial and antioxidant activity

    Science.gov (United States)

    Munteanu, Bogdanel Silvestru; Aytac, Zeynep; Pricope, Gina M.; Uyar, Tamer; Vasile, Cornelia

    2014-10-01

    The antibacterial property of silver nanoparticles (Ag-NPs) and the antioxidant activity of Vitamin E have been combined by incorporation of these two active components within polylactic acid (PLA) nanofibers via electrospinning (PLA/Ag-NP/VitaminE nanofibers). The morphological and structural characterizations of PLA/Ag-NP/VitaminE nanofibers were performed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy and X-ray diffraction. The average fiber diameter was 140 ± 60 nm, and the size of the Ag-NP was 2.7 ± 1.5 nm. PLA/Ag-NP/VitaminE nanofibers inhibited growth of Escherichia coli, Listeria monocytogenes and Salmonella typhymurium up to 100 %. The amount of released Ag ions from the nanofibers immersed in aqueous solution was determined by Inductively Coupled Plasma Mass Spectrometry, and it has been observed that the release of Ag ions was kept approximately constant after 10 days of immersion. The antioxidant activity of PLA/Ag-NP/VitaminE nanofibers was evaluated according to DPPH (2,2-diphenyl-1-picrylhydrazyl) method and determined as 94 %. The results of the tests on fresh apple and apple juice indicated that the PLA/Ag/VitaminE nanofiber membrane actively reduced the polyphenol oxidase activity. The multifunctional electrospun PLA nanofibers incorporating Ag-NP and Vitamin E may be quite applicable in food packaging due to the extremely large surface area of nanofibers along with antibacterial and antioxidant activities. These materials could find application in food industry as a potential preservative packaging for fruits and juices.

  16. Preparation and Characterization of Cationic PLA-PEG Nanoparticles for Delivery of Plasmid DNA

    Directory of Open Access Journals (Sweden)

    Zou Weiwei

    2009-01-01

    Full Text Available Abstract The purpose of the present work was to formulate and evaluate cationic poly(lactic acid-poly(ethylene glycol (PLA-PEG nanoparticles as novel non-viral gene delivery nano-device. Cationic PLA-PEG nanoparticles were prepared by nanoprecipitation method. The gene loaded nanoparticles were obtained by incubating the report gene pEGFP with cationic PLA-PEG nanoparticles. The physicochemical properties (e.g., morphology, particle size, surface charge, DNA binding efficiency and biological properties (e.g., integrity of the released DNA, protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in Hela cells of the gene loaded PLA-PEG nanoparticles were evaluated, respectively. The obtained cationic PLA-PEG nanoparticles and gene loaded nanoparticles were both spherical in shape with average particle size of 89.7 and 128.9 nm, polydispersity index of 0.185 and 0.161, zeta potentials of +28.9 and +16.8 mV, respectively. The obtained cationic PLA-PEG nanoparticles with high binding efficiency (>95% could protect the loaded DNA from the degradation by nuclease and plasma. The nanoparticles displayed sustained-release properties in vitro and the released DNA maintained its structural and functional integrity. It also showed lower cytotoxicity than Lipofectamine 2000 and could successfully transfect gene into Hela cells even in presence of serum. It could be concluded that the established gene loaded cationic PLA-PEG nanoparticles with excellent properties were promising non-viral nano-device, which had potential to make cancer gene therapy achievable.

  17. mPEG-PLA Micelle for Delivery of Effective Parts of Andrographis Paniculata.

    Science.gov (United States)

    Yao, Hailu; Song, Shiyong; Miao, Xiaolu; Liu, Xiao; Zhao, Junli; Wang, Zhen; Shao, Xiaoting; Zhang, Yu; Han, Guang

    2018-01-01

    Many studies have shown that Andrographis paniculata (Burm. f.) Nees has a good anti-tumor effect, but poor solubility in water and poor bioavailability hinder the modernization of it. To formulate the effective parts (mainly diterpene lactones) of Andrographis paniculata (AEP) into targeting drug delivery system, a series of poly(ethylene glycol)-poly(D.L-lactic acid)(mPEG-PLA) with different ratio of hydrophilic and hydrophobic segment was synthetized to encapsulate AEP. AEP micelles were prepared by a simple solvent-evaporation method. According to the loading capacity, the best polymer was chosen. mPEG-PLA micelles were characterized in terms of drug entrapping efficiency, loading capacity, size, the crystalline state of AEP, stability and release profile. Meanwhile, the cytotoxicity of micelles on mouse breast cancer 4T-1 was investigated. These micelle (mPEG-PLA-AEP) particles had a size of (92.84±5.63) nm and a high entrapping efficiency and loading capacity of (91.00±11.53)% and (32.14±3.02)%(w/w), respectively. The powder DSC showed that drugs were well encapsulated in the core of micelles. mPEG-PLA-AEP had a good stability against salt dissociation, protein adsorption and anion substitution and the solubility of andrographolide (AG) and 14-deoxy-11,12-didehydroandrographolide(DDAG) in AEP increased 4.51 times and 2.12 times in water, and the solubility of DAG showed no difference. mPEG-PLA-AEP had the same release profile in different dissolution medium. Cytotoxicity testing in vitro demonstrated that mPEG-PLA-AEP exhibited higher cell viability inhibition in mouse breast cancer 4T-1 than free AEP. mPEG-PLA micelles offer a promising alternative for TCM therapy with higher solubility and improved antitumor effect. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Molecular adaptation of a plant-bacterium outer membrane protease towards plague virulence factor Pla

    Science.gov (United States)

    2011-01-01

    Background Omptins are a family of outer membrane proteases that have spread by horizontal gene transfer in Gram-negative bacteria that infect vertebrates or plants. Despite structural similarity, the molecular functions of omptins differ in a manner that reflects the life style of their host bacteria. To simulate the molecular adaptation of omptins, we applied site-specific mutagenesis to make Epo of the plant pathogenic Erwinia pyrifoliae exhibit virulence-associated functions of its close homolog, the plasminogen activator Pla of Yersinia pestis. We addressed three virulence-associated functions exhibited by Pla, i.e., proteolytic activation of plasminogen, proteolytic degradation of serine protease inhibitors, and invasion into human cells. Results Pla and Epo expressed in Escherichia coli are both functional endopeptidases and cleave human serine protease inhibitors, but Epo failed to activate plasminogen and to mediate invasion into a human endothelial-like cell line. Swapping of ten amino acid residues at two surface loops of Pla and Epo introduced plasminogen activation capacity in Epo and inactivated the function in Pla. We also compared the structure of Pla and the modeled structure of Epo to analyze the structural variations that could rationalize the different proteolytic activities. Epo-expressing bacteria managed to invade human cells only after all extramembranous residues that differ between Pla and Epo and the first transmembrane β-strand had been changed. Conclusions We describe molecular adaptation of a protease from an environmental setting towards a virulence factor detrimental for humans. Our results stress the evolvability of bacterial β-barrel surface structures and the environment as a source of progenitor virulence molecules of human pathogens. PMID:21310089

  19. Cellulose nanocrystals as templates for cetyltrimethylammonium bromide mediated synthesis of Ag nanoparticles and their novel use in PLA films.

    Science.gov (United States)

    Yalcinkaya, E E; Puglia, D; Fortunati, E; Bertoglio, F; Bruni, G; Visai, L; Kenny, J M

    2017-02-10

    In the present paper, we reported how cellulose nanocrystals (CNC) from microcrystalline cellulose have the capacity to assist in the synthesis of metallic nanoparticles chains. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was used as modifier for CNC surface. Silver nanoparticles were synthesized on CNC, and nanoparticle density and size were optimized by varying concentrations of nitrate and reducing agents, and the reduction time. The experimental conditions were optimized for the synthesis and the resulting Ag grafted CNC (Ag-g-CNC) were characterized by means of TGA, SEM, FTIR and XRD, and then introduced in PLA matrix. PLA nanocomposite containing silver grafted cellulose nanocrystals (PLA/0.5Ag-g-1CNC) was characterized by optical and thermal analyses and the obtained data were compared with results from PLA nanocomposites containing 1% wt. of CNC (PLA/1CNC), 0.5% wt. of silver nanoparticles (PLA/0.5Ag) and hybrid system containing CNC and silver in the same amount (PLA/1CNC/0.5Ag). The results demonstrated that grafting of silver nanoparticles on CNC positively affected the thermal degradation process and cold crystallization processes of PLA matrix. Finally, the antibacterial activity of the different systems was studied at various incubation times and temperatures, showing the best performance for PLA/1CNC/0.5Ag based nanocomposite. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Circulating and PBMC Lp-PLA2 associate differently with oxidative stress and subclinical inflammation in nonobese women (menopausal status.

    Directory of Open Access Journals (Sweden)

    Jean Kyung Paik

    Full Text Available BACKGROUND: This study aimed to determine the association of lipoprotein-associated phospholipase A(2 (Lp-PLA(2 activity in circulation and peripheral blood mononuclear cells (PBMCs with inflammatory and oxidative stress markers in nonobese women and according to menopausal status. Lp-PLA(2 activity, a marker for cardiovascular risk is associated with inflammation and oxidative stress. METHODOLOGY/PRINCIPAL FINDINGS: Eighty postmenopausal women (53.0±4.05 yr and 96 premenopausal women (39.7±9.25 yr participated in this study. Lp-PLA(2 activities, interleukin (IL-6, tumor necrosis factor (TNF-α, and IL-1β in plasma as well as in PBMCs were measured. Plasma ox-LDL was also measured. Postmenopausal women demonstrated higher circulating levels of ox-LDL and IL-6, as well as IL-6, TNF-α, and IL-1β in PBMCs, than premenopausal women. In both groups, plasma Lp-PLA(2 activity positively correlated with Lp-PLA(2 activity in PBMCs and plasma ox-LDL. In premenopausal women, Lp-PLA(2 activities in plasma and PBMCs positively correlated with IL-6, TNF-α, and IL-1β in PBMCs. In postmenopausal women, plasma ox-LDL positively correlated with PBMC cytokine production. In subgroup analysis of postmenopausal women according to plasma ox-LDL level (median level: 48.715 U/L, a significant increase in Lp-PLA(2 activity in the plasma but not the PBMCs was found in the high ox-LDL subgroup. Plasma Lp-PLA(2 activity positively correlated with unstimulated PBMC Lp-PLA(2 activity in the low ox-LDL subgroup (r = 0.627, P<0.001, whereas in the high ox-LDL circulating Lp-PLA(2 activity positively correlated with plasma ox-LDL (r = 0.390, P = 0.014 but not with Lp-PLA(2 activity in PBMCs. CONCLUSIONS/SIGNIFICANCE: The lack of relation between circulating Lp-PLA(2 activity and Lp-PLA(2 activity in PBMCs was found in postmenopausal women with high ox-LDL. This may indicate other sources of circulating Lp-PLA(2 activity except PBMC in postmenopausal women

  1. Mechanical Properties and Morphological Characterization of PLA/Chitosan/Epoxidized Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    Zainoha Zakaria

    2013-01-01

    Full Text Available Poly (lactic acid (PLA/chitosan (CS natural polymer/epoxidised natural rubber (ENR composites were successfully prepared through a solution casting method. The morphological characteristics of fabricated composites were investigated by scanning electron microscopy (SEM and optical microscopy. The microstructure of PLA/ENR was significantly altered with the addition of CS. SEM analysis of composites fractured surfaces revealed smooth and homogeneous texture and good dispersion of CS. However for 15 wt% CS composites, the phase segregation and poor adhesion between the polymers were observed. Fourier transform infrared spectroscopy revealed some levels of attractive interaction between CS, PLA, and ENR in the composites. The mechanical properties of composites in terms of tensile strength and tensile modulus were significantly improved with the addition of CS into the matrix while the percent elongation at break decreased. The tensile strength increased up to 5 wt% CS loading for both PLA/CS and PLA/ENR/CS and thereafter decreased while Young’s modulus increased up to 10 wt%. However, when the CS content was increased to 15 wt%, the tensile strength and tensile modulus were slightly decreased. These improvements were attributed to good dispersion of CS at the optimum filler levels and attractive interaction between the composites components.

  2. Impact of the Pla protease substrate α2-antiplasmin on the progression of primary pneumonic plague.

    Science.gov (United States)

    Eddy, Justin L; Schroeder, Jay A; Zimbler, Daniel L; Bellows, Lauren E; Lathem, Wyndham W

    2015-12-01

    Many pathogens usurp the host hemostatic system during infection to promote pathogenesis. Yersinia pestis, the causative agent of plague, expresses the plasminogen activator protease Pla, which has been shown in vitro to target and cleave multiple proteins within the fibrinolytic pathway, including the plasmin inhibitor α2-antiplasmin (A2AP). It is not known, however, if Pla inactivates A2AP in vivo; the role of A2AP during respiratory Y. pestis infection is not known either. Here, we show that Y. pestis does not appreciably cleave A2AP in a Pla-dependent manner in the lungs during experimental pneumonic plague. Furthermore, following intranasal infection with Y. pestis, A2AP-deficient mice exhibit no difference in survival time, bacterial burden in the lungs, or dissemination from wild-type mice. Instead, we found that in the absence of Pla, A2AP contributes to the control of the pulmonary inflammatory response during infection by reducing neutrophil recruitment and cytokine production, resulting in altered immunopathology of the lungs compared to A2AP-deficient mice. Thus, our data demonstrate that A2AP is not significantly affected by the Pla protease during pneumonic plague, and although A2AP participates in immune modulation in the lungs, it has limited impact on the course or ultimate outcome of the infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Snake Venom PLA2s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

    Science.gov (United States)

    Carvalho, B. M. A.; Santos, J. D. L.; Xavier, B. M.; Almeida, J. R.; Resende, L. M.; Martins, W.; Marcussi, S.; Marangoni, S.; Stábeli, R. G.; Calderon, L. A.; Soares, A. M.; Da Silva, S. L.; Marchi-Salvador, D. P.

    2013-01-01

    Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s) are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites. PMID:24171158

  4. Snake Venom PLA2s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

    Directory of Open Access Journals (Sweden)

    B. M. A. Carvalho

    2013-01-01

    Full Text Available Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites.

  5. Partial to complete wetting transitions in immiscible ternary blends with PLA: the influence of interfacial confinement.

    Science.gov (United States)

    Zolali, Ali M; Favis, Basil D

    2017-04-12

    In this study it is shown that the three different intermediate phases in melt blended ternary PLA/PHBV/PBS, PLA/PBAT/PE and PLA/PE/PBAT systems all demonstrate partial wetting, but have very different wetting behaviors as a function of composition and annealing. The interfacial tension of the various components, their spreading coefficients and the contact angles of the confined partially wet droplets at the interface are examined in detail. A wetting transition from partially wet droplets to a complete layer at the interface is observed for both PHBV and PBAT by increasing the concentration and also by annealing. In contrast, in PLA/PE/PBAT, the partially wet droplets of PE at the interface of PLA/PBAT coalesce and grow in size, but remain partially wet even at a high PE concentration of 20% and after 30 min of quiescent annealing. The dewetting speed of the intermediate phase is found to be the principal factor controlling these wetting transitions. This work shows the significant potential for controlled wetting and structuring in ternary polymer systems.

  6. Blends of low molecular weight of poly lactic acid (PLA) with gondorukem (gum rosin)

    Science.gov (United States)

    Kaavessina, Mujtahid; Distantina, Sperisa; Chafidz, Achmad; Utama, Aditya; Anggraeni, Venisa Mega Puteri

    2018-02-01

    The utilization of plastic was increasing as well as the increasing its demand in wide range application. Consequently, the number of plastic litter will increase and make more serious environmental problems. This research concerns to minimize waste problems by designing biodegradable plastic. In this research, biodegradable plastic was made of poly lactic acid (PLA) and gondorukem (Gum rosin, Resina colophonium) as the plasticizer. The effect of gondorukem towards PLA properties such as rheology and degradability was investigated. The research divided into two steps: (i) the polycondensation of lactic acid (LA) and (ii) modification of obtained poly lactic acid. In the first step, polycondensation was done in N2 atmosphere (138°C) for 30 hours and added 0.1 %w of SnCl2 as catalyst. Bulk modification was conducted by blending of gondurukem in varied weight (0.5, 1, and 2 g in 10 g of PLA). Furthermore, the modified PLA was analyzed its molecular structure, biodegradability and rheological property. The presence of gondorukem enhanced the biodegradability of poly lactic acid. Gondorukem could act as the plasticizer. It is confirmed that the complex viscosity of PLA melt decreased upon the addition of gondorukem

  7. PLA and two components silicon rubber blends aiming for frozen foods packaging applications

    Science.gov (United States)

    Meekum, Utai; Khiansanoi, Apichart

    2018-03-01

    Designing of PLA and two components silicone rubber blends was studies. Frozen food packaging application is the main ultimate aim. The statistical method using 23 DOE was conducted. The standard testing methods, in particular impact testing at sub-zero temperature, were performed. The preliminary blend formula comprised 1.0 phr of silane and polyester polyols, respectively, was initially resolved. Then, the optimize the silicone portion in the blends was determined. Blending formula using 8.0 phr of silicone with respect to PLA matrix gave rise to the overall satisfactory properties. 3. TETA was used as the silicone curing agent and reactively blended onto the ingredients. TETA at 0.4 phr, with respect to the silicone, enhanced the mechanical properties, especially flexibility and toughness, of the PLA/silicone blend. Exceeding the optimal TETA loading would cause the chain scission and also the dilution effects. Hence, marginal inferior properties of the blends were be experienced. The preliminary biodegradability investigation found that the PLA/silicone blend initially triggered at the second week. Its degradation rate was likely to be faster than neat PLA.

  8. Synthesis and characterization of curcumin loaded PLA-Hyperbranched polyglycerol electrospun blend for wound dressing applications.

    Science.gov (United States)

    Perumal, Govindaraj; Pappuru, Sreenath; Chakraborty, Debashis; Maya Nandkumar, A; Chand, Dillip Kumar; Doble, Mukesh

    2017-07-01

    This study is aimed to develop curcumin (Cur) incorporated electrospun nanofibers of a blend of poly (lactic acid) (PLA) and hyperbranched polyglycerol (HPG) for wound healing applications. Both the polymers are synthesized and fabricated by electrospinning technique. The produced nanofibers were characterized by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Colorimetry (DSC) and Thermogravimetric Analysis (TGA). Electrospun scaffolds (PLA/HPG/Cur) exhibits very high hydrophilicity, high swelling and drug uptake and promotes better cell viability, adhesion and proliferation when compared to PLA/Cur electrospun nanofibers. Biodegradation study revealed that the morphology of the nanofibers were unaffected even after 14days immersion in Phosphate Buffered Saline. In vitro scratch assay indicates that migration of the cells in the scratch treated with PLA/HPG/Cur is complete within 36h. These results suggest that PLA/HPG/Cur nanofibers can be a potential wound patch dressing for acute and chronic wound applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Functionalized PLA polymers to control loading and/or release properties of drug-loaded nanoparticles.

    Science.gov (United States)

    Thauvin, Cédric; Schwarz, Bettina; Delie, Florence; Allémann, Eric

    2017-11-15

    Advantages associated with the use of polylactic acid (PLA) nano- or microparticles as drug delivery systems have been widely proven in the field of pharmaceutical sciences. These biodegradable and biocompatible carriers have demonstrated different loading and release properties depending on interactions with the cargo, preparation methods, particles size or molecular weight of PLA. In this study, we sought to show the possibility of influencing these properties by modifying the structure of the constituting polymer. Seven non-functionalized or functionalized PLA polymers were specifically designed and synthesized by microwave-assisted ring-opening polymerization of d,l-lactide. They presented short hydrophobic and/or hydrophilic groups thanks to the use of C20 aliphatic chain, mPEG1000, sorbitan esters (Spans ® ) or polysorbates (Tweens ® ), their PEGylated analogues, as initiators. Then, seven types of drug-loaded nanoparticles (NP) were prepared from these polymers and compared in terms of physico-chemical characteristics, drug loading and release profiles. Although the loading properties were not improved with any of the functionalized PLA NP, different release profiles were observed in an aqueous medium at 37 °C and over a period of five days. The presence of PEG moieties in the core of PLA-polysorbates NP induced a faster release while the addition of a single aliphatic chain induced a slower release due to better interactions with the active molecule. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Morphology and thermal properties of PLA films plasticized with aliphatic oligoesters

    International Nuclear Information System (INIS)

    Inacio, Erika M.; Dias, Marcos L.; Lima, Maria Celiana P.

    2015-01-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  11. PLA/PBAT Bionanocomposites with Antimicrobial Natural Rosin for Green Packaging.

    Science.gov (United States)

    Moustafa, Hesham; El Kissi, Nadia; Abou-Kandil, Ahmed I; Abdel-Aziz, Mohamed S; Dufresne, Alain

    2017-06-14

    The use of biodegradable polymers is of great importance nowadays in many applications. Some of the most commonly used biopolymers are polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) due to their superior properties and availability. In this manuscript, we use a facile and green modification method of organoclay (OC) by antimicrobial natural rosin which is considered as a toxicity-free reinforcing material, thus keeping the green character of the material. It increases the interlayer spacing between the clay platelets. This was proven by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and found to impart antimicrobial properties to PLA/PBAT blends. The morphology of the resulting blends was conducted using scanning and transmission electron microscopies (SEM and TEM), and evidence of exfoliation and intercalation was observed. The thermal properties of the blends were studied using differential scanning calorimetry (DSC), and a detailed study of the crystallization of both PLA and PBAT was reported showing cold crystallization behavior of PLA. The final effect on mechanical and antimicrobial properties was also investigated. The obtained results reveal excellent possibility of using expanded OC modified PLA/PBAT polymer blends by adding a green material, antimicrobial natural rosin, for food packaging and biomembranes applications.

  12. Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

    International Nuclear Information System (INIS)

    Murdoch, Dale; McAulay, Laura; Walters, Darren L.

    2014-01-01

    Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy

  13. Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Murdoch, Dale, E-mail: dale_murdoch@health.qld.gov.au [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia); McAulay, Laura [The Prince Charles Hospital, Brisbane (Australia); Walters, Darren L. [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia)

    2014-11-15

    Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy.

  14. Crude extract and purified components isolated from the stems of Tinospora crispa exhibit positive inotropic effects on the isolated left atrium of rats

    DEFF Research Database (Denmark)

    Praman, Siwaporn; Mulvany, Michael J.; Williams, David E.

    2013-01-01

    -butanol soluble material was concentrated and dried under reduced pressure and lyophilized to obtain a crude powder (Tinospora crispa extract). The active components of Tinospora crispa extract were separated by column chromatography and preparative HPLC. The effects and mechanisms of the n-butanol extract...

  15. Effect of composition ratio on the thermal and physical properties of semicrystalline PLA/PHB-HHx composites.

    Science.gov (United States)

    Lim, Jung Seop; Park, Ku-il; Chung, Gun Soo; Kim, Jong Hoon

    2013-05-01

    In this study, composites of semicrystalline, biodegradable polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-HHx) were prepared by direct melt compounding. The physical and thermal properties of the composites were investigated as a function of the composition ratio. Differential scanning calorimetry analysis indicated that PLA and PHB-HHx formed immiscible composites over the observed range of composition. The crystallization of PLA was gradually suppressed by increasing proportions of PHB-HHx. Dynamic mechanical analysis results confirmed that the innate ductility of PHB-HHX and its inhibiting effect on PLA crystallization improved the stiffness of the composite compared to those of neat PLA. The infrared spectra of the immiscible PLA/PHB-HHx composites at two crystallization temperatures (30 °C, 130 °C) were obtained and presented. At 30 °C, PHB-HHx existed as crystalline domains in the PLA matrix, while, amorphous phase of molten PHB-HHx was diffused within the crystalline phase of PLA at 130 °C. The interaction between PHB-HHX and PLA could not be elucidated from the temperature data. Mechanical tests showed that the addition of PHB-HHx improves ductility of PLA/PHB-HHx composite. Morphological analysis revealed that small proportions of PHB-HHx exhibited less tendency to aggregate, which resulted in greater plastic deformation and improved toughness. From this study, PLA blended with small portions of PHB-HHx may further expand the use of bio-friendly resources in a variety of applications such as flexible films, food packaging and something like that. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Enhanced effect of folated pluronic F87-PLA/TPGS mixed micelles on targeted delivery of paclitaxel.

    Science.gov (United States)

    Xiong, Xiang Yuan; Pan, Xiaoqian; Tao, Long; Cheng, Feng; Li, Zi Ling; Gong, Yan Chun; Li, Yu Ping

    2017-10-01

    Targeted drug delivery systems have great potential to overcome the side effect and improve the bioavailability of conventional anticancer drugs. In order to further improve the antitumor efficacy of paclitaxel (PTX) loaded in folated Pluronic F87/poly(lactic acid) (FA-F87-PLA) micelles, D-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS or Vitamin E TPGS) were added into FA-F87-PLA to form FA-F87-PLA/TPGS mixed micelles. The LE of PTX-loaded mixed micelles (13.5%) was highest in the mass ratio 5 to 3 of FA-F87-PLA to TPGS. The in vitro cytotoxicity assays indicated that the IC50 values for free PTX injections, PTX-loaded FA-F87-PLA micelles and PTX-loaded FA-F87-PLA/TPGS mixed micelles after 72h of incubation were 1.52, 0.42 and 0.037mg/L, respectively. The quantitative cellular uptake of coumarin 6-loaded FA-F87-PLA/TPGS and FA-F87-PLA micelles showed that the cellular uptake efficiency of mixed micelles was higher for 2 and 4h incubation, respectively. In vivo pharmacokinetic studies found that the AUC of PTX-loaded FA-F87-PLA/TPGS mixed micelles is almost 1.4 times of that of PTX-loaded FA-F87-PLA micelles. The decreased particle size and inhibition of P-glycoprotein effect induced by the addition of TPGS could result in enhancing the cellular uptake and improving the antitumor efficiency of PTX-loaded FA-F87-PLA/TPGS mixed micelles. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Multimodality Cardiac Imaging for the Assessment of Left Atrial Function and the Association With Atrial Arrhythmias

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Bertelsen, Litten; de Knegt, Martina Chantal

    2016-01-01

    Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function at the c......Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function...... atrial fibrillation, which will be a point of focus in this review. Pivotal cardiac magnetic resonance imaging studies have revealed high correlation between LA fibrosis and risk of atrial fibrillation recurrence after catheter ablation, and subsequent multimodality imaging studies have uncovered...... an inverse relationship between LA reservoir function and degree of LA fibrosis. This has sparked an increased interest into the application of advanced imaging modalities, including both speckle tracking echocardiography and tissue tracking by cardiac magnetic resonance imaging. Even though increasing...

  18. Poly(lactic acid) (PLA) based nanocomposites-a novel way of drug-releasing

    International Nuclear Information System (INIS)

    Chen Chen; Lv Gang; Pan Chao; Song Min; Wu Chunhui; Guo Dadong; Wang Xuemei; Chen Baoan; Gu Zhongze

    2007-01-01

    In this communication, poly(lactic acid) nanofibers have been fabricated by electrospinning and then poly(lactic acid) (PLA) based nanocomposites have been prepared by accumulating anticancer drug daunorubicin on PLA nanofibers combined with TiO 2 nanoparticles. Our atomic force microscopy (AFM) and laser-scanning confocal microscope (LSCM) studies demonstrate that the respective drug molecules could be readily self-assembled on the surface of the blends of nano-TiO 2 with PLA polymer nanocomposites, which could further efficiently facilitate the drug permeation and accumulation on the target leukemia K562 cells. Besides, the respective new nanocomposites have good biocompatibility, ease of surface chemistry modification and very high surface area, which may afford the possibility for their promising application in pharmacology and biomedical engineering areas. (communication)

  19. Optimization in obtaining PLA nanofibers/nHAP for pharmaceuticals release

    International Nuclear Information System (INIS)

    Becaro, A.A.; Paris, E.C.; Mattoso, L.H.C.; Sciena, C.R.; Malafatti, J.D.

    2016-01-01

    Hydroxyapatite (HAP) belongs to the family of calcium apatites. In nanometric form (nHAP) can be used as a drug carrier. The objective was to improve PLA nanofibers with nHAP insert for use in drug delivery. nHAP were obtained by coprecipitation method and characterized by XRD and TEM techniques. PLA fibers (10%) and 5% nHAP were obtained at a distance of 6 cm and flow rate of 0.1, 0.3 and 0.5 ml h"-"1, and characterized by SEM. The nHAP were single phase with rod shape, rounded tip and from 10 to 20 nm in diameter. The fibers obtained from pure PLA had to be more porous than in the presence of HAP. The diameters ranged from 0.2 to 2.4 micrometers. Among the fibers obtained that showed the best result was to flow 0.3 ml h"-"1. (author)

  20. Atmospheric plasma assisted PLA/microfibrillated cellulose (MFC) multilayer biocomposite for sustainable barrier application

    DEFF Research Database (Denmark)

    Meriçer, Çağlar; Minelli, Matteo; Angelis, Maria G De

    2016-01-01

    Fully bio-based and biodegradable materials, such as polylactic acid (PLA) and microfibrillated cellulose (MFC), are considered in order to produce a completely renewable packaging solution for oxygen barrier applications, even at medium-high relative humidity (R.H.). Thin layers of MFC were coated...... on different PLA substrates by activating film surface with an atmospheric plasma treatment, leading to the fabrication of robust and transparent multilayer composite films, which were then characterized by different experimental techniques. UV transmission measurements confirmed the transparency of multilayer...... films (60% of UV transmission rate), while SEM micrographs showed the presence of a continuous, dense and defect free layer of MFC on PLA surface. Concerning the mechanical behavior of the samples, tensile tests revealed that the multilayer films significantly improved the stress at break value of neat...

  1. Enhanced thermal and mechanical properties of PLA/MoS2 nanocomposites synthesized via the in-situ ring-opening polymerization

    Science.gov (United States)

    Chen, Pengpeng; Liang, Xiao; Xu, Ying; Zhou, Yifeng; Nie, Wangyan

    2018-05-01

    In this work, MoS2 nanosheets were employed to reinforce PLA. In order to promote the homogeneous dispersion of MoS2 in PLA and form a strong interface between MoS2 and PLA, the MoS2 nanosheets were firstly modified by mercapto-ethylamine, and then functionalized with PLA chains through ring-opening polymerization of poly(L-lactide). The XRD, XPS, TGA and 1H NMR characterizations confirmed the successful amino and PLA functionalization of MoS2 nanosheets. The obtained MoS2-g-PLA nanosheets were then introduced to reinforce PLA. SEM images displayed that the MoS2-g-PLA nanosheets were dispersed in PLA matrix uniformly. TGA results showed that initial decomposition temperature was improved from 275.6 °C to 334.8 °C with 0.5 wt% of MoS2-g-PLA nanosheets. The storage modulus of PLA/MoS2-g-PLA-0.5 wt% in the glass state and rubber state were both greatly enhanced compared with neat PLA.

  2. Left atrial function in heart failure with impaired and preserved ejection fraction.

    Science.gov (United States)

    Fang, Fang; Lee, Alex Pui-Wai; Yu, Cheuk-Man

    2014-09-01

    Left atrial structural and functional changes in heart failure are relatively ignored parts of cardiac assessment. This review illustrates the pathophysiological and functional changes in left atrium in heart failure as well as their prognostic value. Heart failure can be divided into those with systolic dysfunction and heart failure with preserved ejection fraction (HFPEF). Left atrial enlargement and dysfunction commonly occur in systolic heart failure, in particular, in idiopathic dilated cardiomyopathy. Atrial enlargement and dysfunction also carry important prognostic value in systolic heart failure, independently of known parameters such as left ventricular ejection fraction. In HFPEF, there is evidence of left atrial enlargement, impaired atrial compliance, and reduction of atrial pump function. This occurs not only at rest but also during exercise, indicating significant impairment of atrial contractile reserve. Furthermore, atrial dyssynchrony is common in HFPEF. These factors further contribute to the development of new onset or progression of atrial arrhythmias, in particular, atrial fibrillation. Left atrial function is an integral part of cardiac function and its structural and functional changes in heart failure are common. As changes of left atrial structure and function have different clinical implications in systolic heart failure and HFPEF, routine assessment is warranted.

  3. Involvement of PLA2, COX and LOX in Rhinella arenarum oocyte maturation.

    Science.gov (United States)

    Ortiz, Maria Eugenia; Bühler, Marta Inés; Zelarayán, Liliana Isabel

    2014-11-01

    In Rhinella arenarum, progesterone is the physiological nuclear maturation inducer that interacts with the oocyte surface and starts a cascade of events that leads to germinal vesicle breakdown (GVBD). Polyunsaturated fatty acids and their metabolites produced through cyclooxygenase (COX) and lipoxygenase (LOX) pathways play an important role in reproductive processes. In amphibians, to date, the role of arachidonic acid (AA) metabolites in progesterone (P4)-induced oocyte maturation has not been clarified. In this work we studied the participation of three enzymes involved in AA metabolism - phospholipase A2 (PLA2), COX and LOX in Rhinella arenarum oocyte maturation. PLA2 activation induced maturation in Rhinella arenarum oocytes in a dose-dependent manner. Oocytes when treated with 0.08 μM melittin showed the highest response (78 ± 6% GVBD). In follicles, PLA2 activation did not significantly induce maturation at the assayed doses (12 ± 3% GVBD). PLA2 inhibition with quinacrine prevented melittin-induced GVBD in a dose-dependent manner, however PLA2 inactivation did not affect P4-induced maturation. This finding suggests that PLA2 is not the only phospholipase involved in P4-induced maturation in this species. P4-induced oocyte maturation was inhibited by the COX inhibitors indomethacin and rofecoxib (65 ± 3% and 63 ± 3% GVBD, respectively), although COX activity was never blocked by their addition. Follicles showed a similar response following the addition of these inhibitors. Participation of LOX metabolites in maturation seems to be correlated with seasonal variation in ovarian response to P4. During the February to June period (low P4 response), LOX inhibition by nordihydroguaiaretic acid or lysine clonixinate increased maturation by up to 70%. In contrast, during the July to January period (high P4 response), LOX inhibition had no effect on hormone-induced maturation.

  4. Efficient Degumming of Rice Bran Oil by Immobilized PLA1 from Thermomyces lanuginosus

    Directory of Open Access Journals (Sweden)

    Tripti Singhania

    2015-01-01

    Full Text Available Phospholipase A1 (PLA1 immobilized in calcium alginate can effectively overcome the mass transfer resistance at the lipid-water interface making more room for the enzyme to separate itself from the products of reaction and to bind with the next available molecule at the interface. The reaction of an immobilized PLA1 hydrolase from Thermomyces lanuginosus was comparatively faster than of its free form. The rate of phospholipid hydrolysis by PLA1 was studied in calcium-rich and calcium-depleted environments; and the extent of phosphorus removed from the crude rice bran oil as well as the amount of free fatty acids produced during the reaction were used as indices for analysing the rate of enzymatic hydrolysis under standard conditions of pH, temperature, time of incubation and agitation. The immobilized PLA1 was found to be superior in removing phosphorus in the presencem of 10 mM bivalent calcium ions in a solution. As compared to a maximum of 72.52 % phosphorus removed by 0.01 kg of free enzyme per kg of oil, the same amount of immobilized PLA1 removed phosphorus from oil by 94.12 % under the same experimental conditions (pH=6, 60 °C, 1-hour incubation. Both the free PLA1 and its immobilized form had shown extended rates of hydrolysis in a calcium-rich environment. The mass fractions of free fatty acids produced by the free enzyme and by its immobilized form were 14.9 and 14.16 %, respectively, under the above experimental conditions. The removal of phosphorusfrom oil was accompanied by a signifi cant reduction in colour and restoration of iodine value to the desired level.

  5. Gadolinium-conjugated PLA-PEG nanoparticles as liver targeted molecular MRI contrast agent.

    Science.gov (United States)

    Chen, Zhijin; Yu, Dexin; Liu, Chunxi; Yang, Xiaoyan; Zhang, Na; Ma, Chunhong; Song, Jibin; Lu, Zaijun

    2011-09-01

    A nanoparticle magnetic resonance imaging (MRI) contrast agent targeted to liver was developed by conjugation of gadolinium (Gd) chelate groups onto the biocompatible poly(l-lactide)-block-poly (ethylene glycol) (PLA-PEG) nanoparticles. PLA-PEG conjugated with diethylenetriaminopentaacetic acid (DTPA) was used to formulate PLA-PEG-DTPA nanoparticles by solvent diffusion method, and then Gd was loaded onto the nanoparticles by chelated with the unfolding DTPA on the surface of the PLA-PEG-DTPA nanoparticles. The mean size of the nanoparticles was 265.9 ± 6.7 nm. The relaxivity of the Gd-labeled nanoparticles was measured, and the distribution in vivo was evaluated in rats. Compared with conventional contrast agent (Magnevist), the Gd-labeled PLA-PEG nanoparticles showed significant enhancement both on liver targeting ability and imaging signal intensity. The T(1) and T(2) relaxivities per [Gd] of the Gd-labeled nanoparticles was 18.865 mM(-1) s(-1) and 24.863 mM(-1) s(-1) at 3 T, respectively. In addition, the signal intensity in vivo was stronger comparing with the Gd-DTPA and the T(1) weight time was lasting for 4.5 h. The liver targeting efficiency of the Gd-labeled PLA-PEG nanoparticles in rats was 14.57 comparing with Magnevist injection. Therefore, the Gd-labeled nanoparticles showed the potential as targeting molecular MRI contrast agent for further clinical utilization.

  6. Identification and characterization of phospholipase A2 (PLA2) in bovine pulmonary endothelial cells (BPEC)

    International Nuclear Information System (INIS)

    Martin, T.W.; Wysolmerski, R.B.; Lagunoff, D.

    1986-01-01

    Phosphatidylcholine labeled in the sn-2 position with 3 H-oleic acid was used to measure PLA 2 in cell sonicates (CS) prepared from confluent cultures of BPEC. Substrate at 10-200 μM was incubated with 5-30 μg of CS protein in HEPES buffer at 37 0 C. A plot of 3 H-oleic acid release vs time was linear and proportional to the amount of CS protein. Lineweaver-Burk plots of the data were linear with V/sub max/ = 22.2 nmole/mg protein/hr and K/sub d/ = 121 μM. Under these conditions, phospholipase C activity was 20-fold lower, and phospholipase A 1 activity was not detectable. PLA 2 activity was pH-dependent with optima at 4.5 and 7.5. Ca ++ was not required for activity, and addition of up to 10 mM Ca ++ to CS in EDTA increased activity by only 10-20%. After centrifugation of CS at 100,000 g for 90 min, 62% of the PLA 2 activity was recovered in the particular fraction. Triton X-100 (0.006-0.4%) inhibited PLA 2 up to 90%, whereas 2 mM deoxycholate produced nearly 3-fold activation. Of several agents tested, bromophenacylbromide (BPB) was the most effective inhibitor. Treatment of CS with BPB at 37 0 C for 30 min produced up to 9% inhibition (K/sub i/ = 5 μM). Phenylmethanesulfonyl fluoride at 200 μm produced 41% inhibition. Quinacrine at 1 mM inhibited PLA 2 by 18%. These data define characteristics of BPEC PLA 2 that should prove useful in studies of the role of this enzyme in specific cellular functions

  7. Fabrication of biodegradable PEG-PLA nanospheres for solubility, stabilization, and delivery of curcumin.

    Science.gov (United States)

    Liang, Hongying; Friedman, Joel M; Nacharaju, Parimala

    2017-03-01

    Curcumin is an effective and safe anticancer agent, and also known to induce vasodilation, but its hydrophobicity limits its clinical application. In this study, a simple emulsion method was developed to prepare biodegradable poly (ethylene glycol)-poly (lactic acid) (PEG-PLA) nanospheres to encapsulate curcumin to improve its solubility and stability. The nanoparticle size was around 150 nm with a narrow size distribution. Fluorescence microscopy showed that curcumin encapsulated PEG-PLA nanospheres were taken up rapidly by Hela and MDA-MB-231 cancer cells. This novel nanoparticulate carrier may improve the bioavailability of curcumin without affecting its anticancer properties.

  8. Modificación de las propiedades del ácido Poliláctico (PLA)

    OpenAIRE

    Sáez Morales, Ariel Eduardo

    2013-01-01

    En el proyecto que aquí se presenta se ha realizado un estudio y diferentes ensayos con el objetivo de ver como quedan afectadas las propiedades del Ácido Poliláctico (PLA). El PFC se centra en la modificación de las propiedades térmicas de este polímero mediante el uso de diferentes aditivos que puedan ser capaces de mejorarlas sin afectar decisivamente las otras propiedades del PLA. Se han realizado una serie de experimentos con estos compuestos añadidos y se han observado como afecta...

  9. Attenuation coefficient determination of printed ABS and PLA samples in diagnostic radiology standard beams

    International Nuclear Information System (INIS)

    Veneziani, G.R.; Correa, E.L.; Potiens, M.P.A.; Campos, L.L.

    2015-01-01

    IAEA code of practice TRS-457 states that standard phantoms should offer the same primary attenuation and scatter production as relevant body section of a representative patient. Material cost, availability and dimensional stability must also be considered. The goal of this study is to determine the attenuation coefficient of printed ABS and PLA in standard X-ray beams, verifying if phantoms printed with these materials could be an easier-handle substitute for PMMA, enabling the creation of different designs in an easier and cheaper way. Results show that PMMA presents higher attenuation coefficient, followed by PLA and ABS, which means that thinner PMMA layer creates higher radiation attenuation. (author)

  10. Effect of PBAT on Property of PLA/PHB Film Used for Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Ma Xiuyu

    2017-01-01

    Full Text Available A blend of poly(lactic acid (PLA (70% by weight and poly(3-hydroxybutyrate (PHB (30% by weight with a solubilizing agent (PBAT at four different concentrations (5%, 10%, 15% and 20% by weight per 100 parts of the blends were investigated by FTIR, SEM, mechanical testing, water vapor permeability test and biodegradation studies. SEM showed that PBAT can improve the compatibility between PLA and PHB. The film show a great Oxygen transmission rate and Water vapor permeability property when the content of PBAT is 10%.

  11. Sequential VEGF and BMP-2 releasing PLA-PEG-PLA scaffolds for bone tissue engineering: I. Design and in vitro tests.

    Science.gov (United States)

    Eğri, Sinan; Eczacıoğlu, Numan

    2017-03-01

    Biodegradable PLA-PEG-PLA block copolymers were synthesized with desired backbone structures and molecular weights using PEG20000. Rectangular scaffolds were prepared by freeze drying with or without using NaCl particles. Bone morphogenetic protein (BMP)-2 was loaded to the matrix after the scaffold formation for sustained release while vascular endothelial growth factor (VEGF) was loaded within the pores with gelatin solution. VEGF release was quite fast and almost 60% of it was released in 2 d. However, sequential - sustained released was observed for BMP-2 in the following few months. Corporation of VEGF/BMP-2 couple into the scaffolds increased the cell adhesion and proliferation. Neither significant cytotoxicity nor apoptosis/necrosis were observed.

  12. The PLA2R1-JAK2 pathway upregulates ERRα and its mitochondrial program to exert tumor-suppressive action.

    Science.gov (United States)

    Griveau, A; Devailly, G; Eberst, L; Navaratnam, N; Le Calvé, B; Ferrand, M; Faull, P; Augert, A; Dante, R; Vanacker, J M; Vindrieux, D; Bernard, D

    2016-09-22

    Little is known about the biological role of the phospholipase A2 receptor (PLA2R1) transmembrane protein. In recent years, PLA2R1 has been shown to have an important role in regulating tumor-suppressive responses via JAK2 activation, but the underlying mechanisms are largely undeciphered. In this study, we observed that PLA2R1 increases the mitochondrial content, judged by increased levels of numerous mitochondrial proteins, of the mitochondrial structural component cardiolipin, of the mitochondrial DNA content, and of the mitochondrial DNA replication and transcription factor TFAM. This effect of PLA2R1 relies on a transcriptional program controlled by the estrogen-related receptor alpha1 (ERRα) mitochondrial master regulator. Expression of ERRα and of its nucleus-encoded mitochondrial targets is upregulated upon PLA2R1 ectopic expression, and this effect is mediated by JAK2. Conversely, downregulation of PLA2R1 decreases the level of ERRα and of its nucleus-encoded mitochondrial targets. Finally, blocking the ERRα-controlled mitochondrial program largely inhibits the PLA2R1-induced tumor-suppressive response. Together, our data document ERRα and its mitochondrial program as downstream effectors of the PLA2R1-JAK2 pathway leading to oncosuppression.

  13. The exploration of endocytic mechanisms of PLA-PEG nanoparticles prepared by coaxialtri-capillary electrospray-template removal method.

    Science.gov (United States)

    Chen, Jiaming; Cao, Lihua; Cui, Yuecheng; Tu, Kehua; Wang, Hongjun; Wang, Li-Qun

    2018-01-01

    The nano-sized poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) particles with core-shell structure were efficiently prepared by using coaxial tri-capillary electrospray-template removal method. The cellular uptake mechanism, intracellular distribution and exocytosis in A549 cell model of electrosprayed PLA-PEG nanoparticles were systemically studied. The drug release behavior of electrosprayed PLA-PEG nanoparticles were also investigated. Our results showed that PLA-PEG nanoparticles can be endocytosed quickly by A549 cells. The cellular uptake of PLA-PEG nanoparticles was an energy dependent endocytosis process. Caveolae-mediated endocytosis was only one of endocytosis pathways in A549 cells for PLA-PEG nanoparticles, while clathrin mediated endocytosis was not involved in the endocytosis process. The endocytosed PLA-PEG nanoparticles enriched in the head of A549 cells and only a small amount of them was transported into lysosome after 24h incubation. These findings provided insights into the application of electrosprayed PLA-PEG nanoparticles in nano drug delivery field. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Photo-cross-linked PLA-PEO-PLA hydrogels from self-assembled physical networks: mechanical properties and influence of assumed constitutive relationships.

    Science.gov (United States)

    Sanabria-DeLong, Naomi; Crosby, Alfred J; Tew, Gregory N

    2008-10-01

    Poly(lactide)-block-poly(ethylene oxide)-block-poly(lactide) (PLA-PEO-PLA) triblock copolymers are known to form physical hydrogels in water as a result of the polymer's amphiphilicity. Their mechanical properties, biocompatibility, and biodegradability have made them attractive for use as soft tissue scaffolds. However, the network junction points are not covalently cross-linked, and in a highly aqueous environment these hydrogels adsorb more water, transform from gel to sol, and lose the designed mechanical properties. In this article, a hydrogel was formed by the use of a novel two-step approach. In the first step, the end-functionalized PLA-PEO-PLA triblock was self-assembled into a physical hydrogel through hydrophobic micelle network junctions, and in the second step, this self-assembled physical network structure was locked into place by photo-cross-linking the terminal acrylate groups. In contrast with physical hydrogels, the photo-cross-linked gels remained intact in phosphate-buffered solution at body temperature. The swelling, degradation, and mechanical properties were characterized, and they demonstrated an extended degradation time (approximately 65 days), an exponential decrease in modulus with degradation time, and a tunable shear modulus (1.6-133 kPa). We also discuss the various constitutive relationships (Hookean, neo-Hookean, and Mooney-Rivlin) that can be used to describe the stress-strain behavior of these hydrogels. The chosen model and assumptions used for data fitting influenced the obtained modulus values by as much as a factor of 3.5, which demonstrates the importance of clearly stating one's data fitting parameters so that accurate comparisons can be made within the literature.

  15. Radionuclide detection and differential diagnosis of left-to-right cardiac shunts by analysis of time-activity curves

    International Nuclear Information System (INIS)

    Kim, Ok-Hwa

    1986-01-01

    The noninvasive nature of the radionuclide angiocardiography provided a useful approach for the evaluation of left-to-right cardiac shunts (LRCS). While the qualitative information can be obtained by inspection of serial radionuclide angiocardiograms, the quantitative information of radionuclide angiocardiography can be obtained by the analysis of time-activity curves using advanced computer system. The count ratios method and pulmonary-to-systemic flow ratio (QP/QS) by gamma variate fit method were used to evaluate the accuracy of detection and localization of LRCS. One hundred and ten time-activity curves were analyzed. There were 46 LRCS (atrial septal defects 11, ventricular septal defects 22, patent ductus arteriosus 13) and 64 normal subjects. By computer analysis of time-activity histograms of the right atrium, ventricle and the lungs separately, the count ratios modified by adding the mean cardiac transit time were calculated in each anatomic site. In normal subjects the mean count ratios in the right atrium, ventricle and lungs were 0.24 on average. In atrial septal defects, the count ratios were high in the right atrium, ventricle and lungs, whereas in ventricular septal defects the count ratios were higher only in the right ventricle and lungs. Patent ductus arteriosus showed normal count ratios in the heart but high count ratios were obtained in the lungs. Thus, this count ratios method could be separated normal from those with intracardiac or extracardiac shunts, and moreover, with this method the localization of the shunts level was possible in LRCS. Another method that could differentiate the intracardiac shunts from extracardiac shunts was measuring QP/QS in the left and right lungs. In patent ductus arteriosus, the left lung QP/QS was hight than those of the right lung, whereas in atrial septal defects and ventricular septal defects QP/QS ratios were equal in both lungs. (J.P.N.)

  16. PLA2 - a major regulator of volume-sensitive taurine release in NIH3T3 fibroblasts

    DEFF Research Database (Denmark)

    Lambert, I. H.

    2006-01-01

    -lipoxygenase (5-LO) system is prevented by the 5-LO inhibitor ETH 615-139 and is reduced under hypertonic conditions. Exposure to the amphiphilic bee venom peptide melittin, which has no effect on the kinetic properties of PLA2 but promotes substrate replenishment, induces release of arachidonic acid...... conditions but has only a minor effect on the melittin-induced taurine efflux under hypertonic conditions. Bromoenol lactone and manoalide, known inhibitors of Ca2+-independent phospholipase A2 (iPLA2) and secretory phospholipase A2 (sPLA2), respectively, reduce arachidonic acid and taurine release from NIH3......T3 cells under hypotonic conditions and following addition of melittin. It is suggested that iPLA2/sPLA2 activity is responsible for the volume-sensitivity of taurine release in NIH3T3 mouse fibroblasts....

  17. The clot thickens: an incompletely ligated left  atrial appendage

    Directory of Open Access Journals (Sweden)

    Merrill Thomas

    2018-05-01

    Full Text Available Our patient presented with known mechanical mitral valve endocarditis documented by 2D transesophageal echocardiogram (TOE from a recent hospitalization at an outside facility. On admission to our center, there was no prior knowledge of an incompletely ligated left atrial appendage (LAA according to patient- or family-reported history, review of outside records or the outside facility’s 2D TOE report. A 3D TOE performed at our center to assess her pathology, since a month had passed from her prior hospitalization, revealed a LAA ligation with evidence of communication to the left atrium and with clot present in the appendage. This case report highlights the common finding of incomplete closure of the LAA following surgical ligation, thus making it inadequate for stroke prevention in patients with atrial fibrillation, and that 3D TOE plays a valuable role in assessing the durability of LAA ligation.

  18. The Hispanic Monarchy in the Era of the Holy Spirit: the Atrium of Valadés

    Directory of Open Access Journals (Sweden)

    Guillermo Serés

    2017-11-01

    Full Text Available The autghor of this article analyse the influence of the work of the Millenarian Joaquin Da Fiore, Ramon Llull and Arias Montano on the composition of Christian Rhetoric by Diego Valadés. From the first of these writers, the author takes the notion of the era of the Holy Spirit; from the second, the concept of the Earthly City, for conquering the Indians; from the third, an idea for an engraving of significance in Valadés’ book, namely, the convent atrium. Additionally, he also take into account the idea of restitutio and reductio ad unum, with which both the mission of his Franciscan order and that of the Spanish monarchy are justified.

  19. [The vulnerability of the human atrium. I. Correlations between vulnerability, sinus node recovery time and intraatrial conduction time (author's transl)].

    Science.gov (United States)

    Pop, T; Fleischmann, D; Effert, S

    1976-09-01

    Using the extrastimulus method in 100 patients, premature impulses were applied during the relative refractory period of the right atrium. Depending on the atrial response to these impulses we divided our patients in the following 3 groups: Group A: no repetitive firing (61 patients); group B: 1 to 5 additional atrial extrasystoles with a total duration of maximum 1.5 s (27 patients); group C: runs of atrial flutter or fibrilation for at least 8 s (12 patients). The statistical analysis of the following parameters: age, PA interval, absolute and corrected sinus node recovery time did not show any significant difference between the 3 groups. These results suggest that the investigated parameters are of no great importance in the genesis of the atrial vulnerability.

  20. Successful ablation of a right atrium-axillary ventricular accessory pathway associated with Wolff-Parkinson-White syndrome.

    Science.gov (United States)

    Yuan, Yuan; Long, Deyong; Dong, Jianzeng; Tao, Ling; Ma, Changsheng

    2017-12-01

    We report a case of a patient with right axillary ventricular. Similar congenital anomaly of the right atrium was reported as "right appendage diverticulum or right atrial diverticulum." However, this independent chamber has its own annulus, synchronizes with the right ventricular, and generates large ventricular potential. Under the guidance of the CARTO mapping system (Biosense Webster, Diamond Bar, CA, USA), a right atrioventricular accessory pathway associated with type B Wolff-Parkinson-White syndrome was ablated successfully. This pathway was close to the annulus of the axillary ventricular. The patient remained free of arrhythmia at 1-year follow-up. © 2017 Wiley Periodicals, Inc.

  1. Improved design and characterization of PLGA/PLA-coated Chitosan based micro-implants for controlled release of hydrophilic drugs.

    Science.gov (United States)

    Manna, Soumyarwit; Donnell, Anna M; Kaval, Necati; Al-Rjoub, Marwan F; Augsburger, James J; Banerjee, Rupak K

    2018-05-29

    Repetitive intravitreal injections of Methotrexate (MTX), a hydrophilic chemotherapeutic drug, are currently used to treat selected vitreoretinal (VR) diseases, such as intraocular lymphoma. To avoid complications associated with the rapid release of MTX from the injections, a Polylactic acid (PLA) and Chitosan (CS)-based MTX micro-implant prototype was fabricated in an earlier study, which showed a sustained therapeutic release rate of 0.2-2.0 µg/day of MTX for a period ∼1 month in vitro and in vivo. In the current study, different combinations of Poly(lactic-co-glycolic) acid (PLGA)/PLA coatings were used for lipophilic surface modification of the CS-MTX micro-implant, such as PLGA 5050, PLGA 6535 and PLGA 7525 (PLA: PGA - 50:50, 65:35, 75:25, respectively; M.W: 54,400 - 103,000) and different PLA, such as PLA 100 and PLA 250 (MW: 102,000 and 257,000, respectively). This improved the duration of total MTX release from the coated CS-MTX micro-implants to ∼3-5 months. With an increase in PLA content in PLGA and molecular weight of PLA, a) the initial burst of MTX and the mean release rate of MTX can be reduced; and b) the swelling and biodegradation of the micro-implants can be delayed. The controlled drug release mechanism is caused by a combination of diffusion process and hydrolysis of the polymer coating, which can be modulated by a) PLA content in PLGA and b) molecular weight of PLA, as inferred from Korsmeyer Peppas model, Zero order, First order and Higuchi model fits. This improved micro-implant formulation has the potential to serve as a platform for controlled release of hydrophilic drugs to treat selected VR diseases. Copyright © 2018. Published by Elsevier B.V.

  2. Numerical investigations of buoyancy-driven natural ventilation in a simple three-storey atrium building and thermal comfort evaluation

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2013-01-01

    The numerical investigations of buoyancy-driven natural ventilation and thermal comfort evaluation in a simple three-storey atrium building as a part of the passive ventilation strategy was undertaken using a validated Computational Fluid Dynamic (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modeling approach with the SST-k–ω turbulence model and the discrete transfer radiation model (DTRM) was used for the numerical investigations. The steady-state governing equations were solved using a commercial solver FLUENT©. Various flow situations of the buoyancy-driven natural ventilation in the building during day and night time were examined. The numerical results obtained for the airflow rates, airflow patterns and temperature distributions inside the building are presented in this paper. Using the numerical results, the well-known thermal comfort indices PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for the evaluation of the thermal comfort conditions in the occupied regions of the building. It was noticed that thermal conditions prevailing in the occupied areas of the building as a result of using the buoyancy-driven ventilation were mostly in comfort zone. From the study of the night time ventilation, it was found that hot water (80 °C) circulation (heated by solar collectors during daytime) along the chimney walls during night time and heat sources present in the building can be useful in inducing night ventilation airflows in the building as a part of the passive ventilation strategy. -- Highlights: • A simple three-storey atrium building. • Numerical modeling of buoyancy-driven ventilation flow in the building. • Effect of solar intensity and geographical location on ventilation. • CFD predictions were used to calculate thermal comfort indices. • Evaluation of thermal comfort conditions for the occupants

  3. Left heart ventricular angiography

    Science.gov (United States)

    ... blood vessels. These x-ray pictures create a "movie" of the left ventricle as it contracts rhythmically. ... 22578925 www.ncbi.nlm.nih.gov/pubmed/22578925 . Review Date 9/26/2016 Updated by: Michael A. ...

  4. Left heart catheterization

    Science.gov (United States)

    Catheterization - left heart ... to help guide the catheters up into your heart and arteries. Dye (sometimes called "contrast") will be ... in the blood vessels that lead to your heart. The catheter is then moved through the aortic ...

  5. The importance of integrated left atrial evaluation: From hypertension to heart failure with preserved ejection fraction.

    Science.gov (United States)

    Beltrami, Matteo; Palazzuoli, Alberto; Padeletti, Luigi; Cerbai, Elisabetta; Coiro, Stefano; Emdin, Michele; Marcucci, Rossella; Morrone, Doralisa; Cameli, Matteo; Savino, Ketty; Pedrinelli, Roberto; Ambrosio, Giuseppe

    2018-02-01

    Functional analysis and measurement of left atrium are an integral part of cardiac evaluation, and they represent a key element during non-invasive analysis of diastolic function in patients with hypertension (HT) and/or heart failure with preserved ejection fraction (HFpEF). However, diastolic dysfunction remains quite elusive regarding classification, and atrial size and function are two key factors for left ventricular (LV) filling evaluation. Chronic left atrial (LA) remodelling is the final step of chronic intra-cavitary pressure overload, and it accompanies increased neurohormonal, proarrhythmic and prothrombotic activities. In this systematic review, we aim to purpose a multi-modality approach for LA geometry and function analysis, which integrates diastolic flow with LA characteristics and remodelling through application of both traditional and new diagnostic tools. The most important studies published in the literature on LA size, function and diastolic dysfunction in patients with HFpEF, HT and/or atrial fibrillation (AF) are considered and discussed. In HFpEF and HT, pulsed and tissue Doppler assessments are useful tools to estimate LV filling pressure, atrio-ventricular coupling and LV relaxation but they need to be enriched with LA evaluation in terms of morphology and function. An integrated evaluation should be also applied to patients with a high arrhythmic risk, in whom eccentric LA remodelling and higher LA stiffness are associated with a greater AF risk. Evaluation of LA size, volume, function and structure are mandatory in the management of patients with HT, HFpEF and AF. A multi-modality approach could provide additional information, identifying subjects with more severe LA remodelling. Left atrium assessment deserves an accurate study inside the cardiac imaging approach and optimised measurement with established cut-offs need to be better recognised through multicenter studies. © 2017 John Wiley & Sons Ltd.

  6. Unsuccessful lung scan due to major right-to-left shunt through a sinus venosus septal defect

    International Nuclear Information System (INIS)

    Brendel, A.J.; Larnaudie, B.; Lambert, B.; Leccia, F.; Barat, J.L.; Ducassou, D.; Fontan, F.

    1985-01-01

    In a patient with a prior history of cerebral abscess and cerebral ischemia, an unsuccessful perfusion lung scan led to a radionuclide angiocardiogram using an arm vein injection. This showed a total right-to-left (R-L) shunt from the superior vena cava (SVC) to the left atrium. Repeat radionuclide study, through a leg vein, demonstrated a moderate R-L shunt and an interpretable lung scan could be obtained. Catheterization and contrast cineangiogram did not provide the exact diagnosis, the preoperative conclusion being anomalous drainage of the SVC into the left atrium, with atrial septal defect (ASD) and partial anomalous pulmonary venous connection to the SVC. The operative diagnosis was high atrial (sinus venosus) septal defect. This example of major but clinically unsuspected R-L shunt emphasizes the value of performing a perfusion lung scan, preferably in conjunction with radionuclide angiocardiography in patients with a prior history of unexplained cerebral abscess or systemic ischemia. Implications of the site of an ASD on quantitation of L-R shunts by radionuclide methods are also discussed

  7. Correlation between crystallization behaviour and interfacial interactions in plasticized PLA/POSS nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kodal, Mehmet, E-mail: mehmet.kodal@kocaeli.edu.tr; Şirin, Hümeyra; Özkoç, Güralp, E-mail: guralp.ozkoc@kocaeli.edu.tr [Department of Chemical Engineering, Kocaeli University, 41380, Kocaeli Turkey (Turkey)

    2016-03-09

    In this study, the correlation between crystallization behavior and surface chemistry of polyhedral oligomeric silsesquioxanes (POSS) for plasticized poly(lactic acid) (PLA)/POSS nanocomposites was investigated. Four different kinds of POSS particles having different chemical structures were used. Poly(ethylene glycol) (PEG, 8000 g/mol) was utilized as the plasticiser. The nanocomposites were melt-compounded in an Xplore Instruments 15 cc twin screw microcompounder at 180°C barrel temperature and 100 rpm screw speed. Non-isothermal crystallization behaviour of PLA/PEG/POSS nanocomposites were evaluated from common kinetic models such as Avrami and Avrami-Ozawa and Kissinger by using the thermal data obtained from differantial scanning calorimetry (DSC). A polarized optical microscope (POM) equipped with a hot-stage was used to examine the morphology during the crystal growth. In order to investigate the interfacial interactions between POSS particles and plasticized PLA, thermodynamic work of adhesion approach was adopted using the experimentally determined surface energies. A strong correlation was obtained between interfacial chemistry and the nucleation rate in plasticized PLA/POSS nanocomposites. It was found that the polar interactions were the dominating factor which determines the nucleation activity of the POSS particles.

  8. Manipulating dispersion and distribution of graphene in PLA through Novel Interface Engineering for improved conductive properties

    Science.gov (United States)

    This study aimed to enhance the conductive properties of PLA nanocomposite by controlling the dispersion and distribution of graphene within the minor phase of the polymer blend. Functionalized graphene (f-GO) was achieved by reacting graphene oxide (GO) with various silanes under the aid of an ioni...

  9. Processing and characterization of plasticized PLA/PHB blends for biodegradable multiphase systems

    Directory of Open Access Journals (Sweden)

    I. Armentano

    2015-07-01

    Full Text Available Blends of poly(lactic acid (PLA and poly(3-hydroxybutyrate (PHB plasticized with a lactic acid oligomer (OLA added at three different concentrations (15, 20 and 30 wt% by weight, were prepared by an optimized extrusion process to improve the processability and mechanical properties of these biopolymers for flexible film manufacturing. Morphological, chemical, thermal, mechanical, barrier and migration properties were investigated and formulations with desired performance in eco-friendly films were selected. The efficiency of OLA as plasticizer for PLA_PHB blends was demonstrated by the significant decrease of their glass transition temperatures and a considerable improvement of their ductile properties. The measured improvements in the barrier properties are related to the higher crystallinity of the plasticized PLA_PHB blends, while the overall migration test underlined that all the proposed formulations maintained migration levels below admitted levels. The PLA_PHB blend with 30 wt% OLA was selected as the optimum formulation for food packaging, since it offered the best compromise between ductility and oxygen and water vapor barrier properties with practically no migration.

  10. Serum Lp-PLA2: as a novel viewpoint in periodontal treatment of hyperlipidaemics.

    Science.gov (United States)

    Fentoğlu, Özlem; Kirzioğlu, Fatma Yeşim; Tözüm Bulut, Memduha; Kurgan, Şivge; Koçak, Havva; Sütcü, Recep; Kale Köroğlu, Banu; Günhan, Meral

    2015-01-01

    To evaluate the effects of periodontal treatment on serum lipoprotein-associated phospholipase A2 (Lp-PLA2) and C-reactive protein (CRP) levels in hyperlipidaemic patients with periodontitis. The study included 52 hyperlipidaemics and 28 systemically healthy controls (C) with periodontitis. Of the 52 hyperlipidaemics, 29 received a suggested diet (HD), and 23 of them were prescribed statin (HS). Clinical periodontal parameters, serum lipids, Lp-PLA2, and CRP levels were assessed at the baseline and 2 months after the completion of the nonsurgical periodontal treatment (2MPT). Serum parameters were also evaluated 1 week following the periodontal treatment (1WPT). At the baseline, patients in the HS group had a higher percentage of bleeding on probing than those in the C and HD groups. Hyperlipidaemics had higher serum triglyceride levels than the control group at 2MPT compared to the baseline. At 2MPT, the levels of Lp-PLA2 in the HS group were significantly higher compared to the baseline and 1WPT. There were no statistically significant differences in CRP levels between study periods for all groups. The periodontal treatment may affect the inflammatory control of hyperlipidaemic patients with periodontitis via increased Lp-PLA2 levels and severity of the impaired lipid metabolism. These findings may be important regarding the therapeutic strategies for hyperlipidaemics with periodontitis.

  11. Enzymatic degradation behavior of nanoclay reinforcedbiodegradable PLA/PBSA blend composites

    CSIR Research Space (South Africa)

    Malwela, T

    2015-06-01

    Full Text Available Journal of Biological Macromolecules Vol. 77, 131-142 Enzymatic degradation behavior of nanoclay reinforcedbiodegradable PLA/PBSA blend composites Thomas Malwelaa,b, Suprakas Sinha Raya,b,∗ aDST/CSIR National Centre for Nanostructured Materials...

  12. Maslinic acid modulates secreted phospholipase A2-IIA (sPLA2-IIA ...

    Indian Academy of Sciences (India)

    Wei Hsum Yap

    2018-03-29

    Mar 29, 2018 ... Further analysis revealed that sPLA2-IIA only induced modest LDL oxidation and that inhibitory .... COX-2, was also reduced in primary human chondrocyte, primary rat .... oxidation (4.34 nmol MDA/mg protein) compared to native ..... rheumatoid fibroblast-like synoviocyte arachidonic acid meta- bolism.

  13. Interactions of pharmacologically active snake venom sPLA2 with different cell lines

    Science.gov (United States)

    Doumanov, Jordan; Mladenova, Kirilka; Aleksandrov, Radoslav; Danovski, Georgi; Petrova, Svetla

    2014-01-01

    Secreted Phospholipases A2 (sPLA2s) represent a large family of structurally related enzymes, which target different tissues and organs and induce numerous pharmacological effects based on their catalytic specificity – hydrolysis of the sn-2 ester bond of glycerophospholipids. The neurotoxin vipoxin, isolated from the venom of Vipera ammodytes meriodionalis, is a heterodimeric postsynaptic ionic complex composed of two protein subunits – a basic and toxic His48 sPLA2 enzyme and an acidic, enzymatically inactive and non-toxic component. In this paper, for the first time, we demonstrate that vipoxin sPLA2 enzyme affects cell integrity and viability of four cell types and causes different cell responses. The most dramatic local tissue effects were observed with RPE-1 (retinal pigment epithelial) cells followed by A549 (adenocarcinomic human alveolar epithelial) cells and MDCK (Madin-Darby Canine Kidney epithelial) cells. Products of the enzymatic reaction, lysophospholipids and unsaturated free fatty acids, act as lipid mediators that can induce membrane damaging or can stimulate cell proliferation. Our preliminary results on the cytotoxic effect of vipoxin sPLA2 on A549 cells are promising in searching of its eventual anticancer potential. PMID:26019578

  14. Effects of modified cellulose nanocrystals on the barrier and migration properties of PLA nano-biocomposites.

    Science.gov (United States)

    Fortunati, E; Peltzer, M; Armentano, I; Torre, L; Jiménez, A; Kenny, J M

    2012-10-01

    The aim of this paper is to report the impact of the addition of cellulose nanocrystals on the barrier properties and on the migration behaviour of poly(lactic acid), PLA, based nano-biocomposites prepared by the solvent casting method. Their microstructure, crystallinity, barrier and overall migration properties were investigated. Pristine (CNC) and surfactant-modified cellulose nanocrystals (s-CNC) were used, and the effect of the cellulose modification and content in the nano-biocomposites was investigated. The presence of surfactant on the nanocrystal surface favours the dispersion of CNC in the PLA matrix. Electron microscopy analysis shows the good dispersion of s-CNC in the nanoscale with well-defined single crystals indicating that the surfactant allowed a better interaction between the cellulose structures and the PLA matrix. Reductions of 34% in water permeability were obtained for the cast films containing 1 wt.% of s-CNC while good oxygen barrier properties were detected for nano-biocomposites with both 1 wt.% and 5 wt.% of modified and un-modified cellulose nanocrystals, underlining the improvement provided by cellulose on the PLA films. Moreover, the migration level of the studied nano-biocomposites was below the overall migration limits required by the current normative for food packaging materials in both non-polar and polar simulants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Comportement en fatigue et influence de la temperature sur les proprietes en traction du PLA

    Science.gov (United States)

    Menard, Claire

    Current environmental issues reduce the use of materials obtained from fossil resources. The usual plastics therefore tend to be replaced by more green polymers such as polylactic acid (PLA), a bio-based and biodegradable polymer. Knowledge on the properties of this material is essential, especially in terms of fatigue strength and influence of temperature on tensile stiffness and strength. In this study, the PLA samples are submitted to monotonic tensile tests, according to ASTM D638-10, at various temperatures between room temperature (23°C) and the glass transition temperature of the material (55-60°C). The results show a decrease of 30% of the modulus of elasticity and 60% of the tensile strength between these two temperatures. This decrease is mainly due to a significant drop in the mechanical properties beyond 50°C. In addition, tensile fatigue tests were conducted at loads rate between 40 and 80% of tensile strength, at room temperature in order to plot the Wohler curve of PLA. The ruptured specimens were finally observed with a scanning electron microscope (SEM) to analyze the failure mechanisms in fatigue of PLA.

  16. Preparation and properties of Starch-g-PLA/poly(vinyl alcohol) composite film.

    Science.gov (United States)

    Hu, Yingmo; Wang, Qingling; Tang, Mingru

    2013-07-25

    Starch/lactic acid graft copolymer (Starch-g-PLA) was prepared by the in situ copolymerization of starch grafted with lactic acid catalyzed with sodium hydroxide, and then mixed with poly(vinyl alcohol) (PVA) to get composite films. The structures of the graft copolymer and composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties, water resistance, and thermal stability were also investigated. It was found that the compatibility of Starch-g-PLA and PVA was better than that of starch and PVA in the composite films. The tensile strength and elongation at break of the Starch-g-PLA/PVA composite film increased by 69.15% and 84.22%, respectively, while the water absorption decreased by 50.39%, which overcame the shortcomings of hydrophilicity and poor mechanical properties of Starch/PVA film. Thermogravimetric analysis (TGA) also showed that the thermal stability of Starch-g-PLA/PVA film was improved compared with Starch/PVA film. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Thermal, mechanical and morphological characterization of plasticized PLA-PHB blends

    Science.gov (United States)

    A blend of poly(lactic acid) (PLA) (75% by weight) and poly(3-hydroxybutyrate) (PHB) (25% by weight) with a polyester plasticizer (Lapol 108) at two different concentrations (5 and 7% by weight per 100 parts of the blends) were investigated by TGA, DSC, XRD, SEM, mechanical testing and biodegradatio...

  18. Preparation and mechanical properties of modified nanocellulose/PLA composites from cassava residue

    Directory of Open Access Journals (Sweden)

    Lijie Huang

    2018-02-01

    Full Text Available Nanocellulose was prepared by a mechanochemical method using cassava residue as a raw material and phosphoric acid as the auxiliary agent. The prepared nanocellulose was hydrophobically modified with stearic acid to improve its dispersibility. This modified nanocellulose was added to polylactic acid (PLA film-forming liquids at concentrations of 0%, 0.5%, 1.0%, 1.5% and 2.0%, and the effect of modified nanocellulose on the mechanical properties of polylactic acid (PLA films were investigated. When at least 0.5% modified nanocellulose is added, more active groups of modified nanocellulose are adsorbed onto the PLA molecular chain. Although the tensile strength of the film is only improved by 13.59%, the flexibility of the film decreases, and the elastic modulus decreases by 28.91%. When 1% modified nanocellulose is added, the modified nanocellulose and PLA are tangled together through molecular chains and they co-crystallize to form a stable network structure. The tensile strength of the nanocomposite films is enhanced by 40.03%, the elastic modulus is enhanced by 55.65%, and the flexibility of the film decreases.

  19. Effect of nanoclay on optical properties of PLA/clay composite films

    CSIR Research Space (South Africa)

    Cele, HM

    2014-06-01

    Full Text Available function of the clay loading. The optical properties of the PLA/OMMT composites were studied using variable angle spectroscopic ellipsometry (VASE) and ultra-violet (UV-Vis) spectroscopy. VASE revealed that the refractive index and extinction coefficient (n...

  20. Optimisation of mechanical properties of bamboo fibre reinforced-PLA biocomposites

    Science.gov (United States)

    Nurnadia M., J.; Fazita, M. R. Nurul; Abdul Khalil H. P., S.; Mohamad Haafiz M., K.

    2017-12-01

    The majority of the raw materials that have been widely used in industries are petroleum-based. Growing environmental awareness, the depletion of fossil fuels, and climate change are the key drivers to seek more ecologically friendly materials, such as natural fibres to replace synthetic fibres in polymeric composite. Among the natural fibres available, bamboo fibre has relatively high strength. Poly (lactic) acid (PLA), one of the well-known biopolymers, has been used as a matrix in order to produce totally biodegradable biocomposites. In this study, bamboo fibres were compounded with PLA by a twin screw extruder. The bamboo fibre reinforced PLA composites were then manufactured via the compression moulding method. The influences of screw speed and die temperature during extrusion on the mechanical properties, the tensile and flexural of the biocomposites, were studied. The effects of fibre content and fibre length were also investigated. Taguchi experimental design approach was adopted to determine the optimum set of conditions to achieve the "best" mechanical properties of the composites. Tensile and flexural properties were characterised based on the D638-10 and D790-10 standards, respectively. It was observed that the fibre aspect ratio and fibre content significantly affected the mechanical performance of bamboo fibres reinforced PLA composites.

  1. Correlation between crystallization behaviour and interfacial interactions in plasticized PLA/POSS nanocomposites

    International Nuclear Information System (INIS)

    Kodal, Mehmet; Şirin, Hümeyra; Özkoç, Güralp

    2016-01-01

    In this study, the correlation between crystallization behavior and surface chemistry of polyhedral oligomeric silsesquioxanes (POSS) for plasticized poly(lactic acid) (PLA)/POSS nanocomposites was investigated. Four different kinds of POSS particles having different chemical structures were used. Poly(ethylene glycol) (PEG, 8000 g/mol) was utilized as the plasticiser. The nanocomposites were melt-compounded in an Xplore Instruments 15 cc twin screw microcompounder at 180°C barrel temperature and 100 rpm screw speed. Non-isothermal crystallization behaviour of PLA/PEG/POSS nanocomposites were evaluated from common kinetic models such as Avrami and Avrami-Ozawa and Kissinger by using the thermal data obtained from differantial scanning calorimetry (DSC). A polarized optical microscope (POM) equipped with a hot-stage was used to examine the morphology during the crystal growth. In order to investigate the interfacial interactions between POSS particles and plasticized PLA, thermodynamic work of adhesion approach was adopted using the experimentally determined surface energies. A strong correlation was obtained between interfacial chemistry and the nucleation rate in plasticized PLA/POSS nanocomposites. It was found that the polar interactions were the dominating factor which determines the nucleation activity of the POSS particles.

  2. PLA and single component silicone rubber blends for sub-zero temperature blown film packaging applications

    Science.gov (United States)

    Meekum, Utai; Khiansanoi, Apichart

    2018-06-01

    The poly(lactic acid) (PLA) blend with single component silicone rubber in the presence of reactive amino silane coupling agent and polyester polyols plasticizer were studied. The manufacturing of film packaging for sub-zero temperature applications from the PLA blend was the main objective. The mechanical properties, especially the impact strengths, of PLA/silicone blends were significantly depended on the silicone loading. The outstanding impact strengths, tested at sub-zero temperature, of the blend having silicone content of 8.0 phr was achieved. It was chosen as the best candidate for the processability improvement. Adding the talc filler into the PLA/silicone blend to enhance the rheological properties was investigated. The ductility of the talc filled blends were decreased with increasing the filler contents. However, the shear viscosity of the blend was raised with talc loading. The blend loaded with 40 phr of talc filler was justified as the optimal formula for the blown film process testing and it was successfully performed with a few difficulties. The obtained blown film showed relative good flexibility in comparison with LDPE but it has low transparency.

  3. VT-NRK Toepassing bioplastics : verbeteren van de technische eigenschappen van PLA-folies

    NARCIS (Netherlands)

    Molenveld, K.; Schennink, G.G.J.

    2009-01-01

    Het doel van dit project, VT-NRK toepassing bioplastics, is het genereren en verspreiden van kennis met betrekking tot het verbeteren van de technische eigenschappen van PLA folies. De kennis is bedoeld voor de bedrijven die binnen de kunststofindustrie aangesloten zijn bij de MJA én folies

  4. A New Approach to PLA Using Scholarships and an Audit Tool

    Science.gov (United States)

    Adams, Shirley M.; Wilder, Linda

    2016-01-01

    The history of Prior Learning Assessment (PLA) can be traced back to World War II when the American Council on Education (ACE) began conducting credit evaluations of military training. However, it wasn't until the 1970s with the inception of adult-serving colleges such as Charter Oak State College (COSC) and others, the altering of ACE to expand…

  5. PHEA-PLA biocompatible nanoparticles by technique of solvent evaporation from multiple emulsions.

    Science.gov (United States)

    Cavallaro, Gennara; Craparo, Emanuela Fabiola; Sardo, Carla; Lamberti, Gaetano; Barba, Anna Angela; Dalmoro, Annalisa

    2015-11-30

    Nanocarriers of amphiphilic polymeric materials represent versatile delivery systems for poorly water soluble drugs. In this work the technique of solvent evaporation from multiple emulsions was applied to produce nanovectors based on new amphiphilic copolymer, the α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-polylactic acid (PHEA-PLA), purposely synthesized to be used in the controlled release of active molecules poorly soluble in water. To this aim an amphiphilic derivative of PHEA, a hydrophilic polymer, was synthesized by derivatization of the polymeric backbone with hydrophobic grafts of polylactic acid (PLA). The achieved copolymer was thus used to produce nanoparticles loaded with α tocopherol (vitamin E) adopted as lipophilic model molecule. Applying a protocol based on solvent evaporation from multiple emulsions assisted by ultrasonic energy and optimizing the emulsification process (solvent selection/separation stages), PHEA-PLA nanostructured particles with total α tocopherol entrapment efficiency (100%), were obtained. The drug release is expected to take place in lower times with respect to PLA due to the presence of the hydrophilic PHEA, therefore the produced nanoparticles can be used for semi-long term release drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Preparation and mechanical properties of modified nanocellulose/PLA composites from cassava residue

    Science.gov (United States)

    Huang, Lijie; Zhang, Xiaoxiao; Xu, Mingzi; Chen, Jie; Shi, Yinghan; Huang, Chongxing; Wang, Shuangfei; An, Shuxiang; Li, Chunying

    2018-02-01

    Nanocellulose was prepared by a mechanochemical method using cassava residue as a raw material and phosphoric acid as the auxiliary agent. The prepared nanocellulose was hydrophobically modified with stearic acid to improve its dispersibility. This modified nanocellulose was added to polylactic acid (PLA) film-forming liquids at concentrations of 0%, 0.5%, 1.0%, 1.5% and 2.0%, and the effect of modified nanocellulose on the mechanical properties of polylactic acid (PLA) films were investigated. When at least 0.5% modified nanocellulose is added, more active groups of modified nanocellulose are adsorbed onto the PLA molecular chain. Although the tensile strength of the film is only improved by 13.59%, the flexibility of the film decreases, and the elastic modulus decreases by 28.91%. When 1% modified nanocellulose is added, the modified nanocellulose and PLA are tangled together through molecular chains and they co-crystallize to form a stable network structure. The tensile strength of the nanocomposite films is enhanced by 40.03%, the elastic modulus is enhanced by 55.65%, and the flexibility of the film decreases.

  7. The use of chitosan/PLA nano-fibers by emulsion eletrospinning for periodontal tissue engineering.

    Science.gov (United States)

    Shen, Renze; Xu, Weihong; Xue, Yanxiang; Chen, Luyuan; Ye, Haicheng; Zhong, Enyi; Ye, Zhanchao; Gao, Jie; Yan, Yurong

    2018-04-16

    In this study, nanofibrous scaffolds base on pure polylactic acid (PLA) and chitosan/PLA blends were fabricated by emulsion eletrospinning. By modulating their mechanical and biological properties, cell-compatible and biodegradable scaffolds were developed for periodontal bone regeneration. Pure PLA and different weight ratios of chitosan nano-particle/PLA nano-fibers were fabricated by emulsion eletrospinning. Scanning electron microscope (SEM) was performed to observe the morphology of nano-fibers. Mechanical properties of nano-fibers were tested by single fiber strength tester. Hydrophilic/hydrophobic nature of the nano-fibers was observed by stereomicroscope. In vitro degradation was also tested. Cells were seeded on nano-fibers scaffolds. Changes in cell adhesion, proliferation and osteogenic differentiation were tested by MTT assay and Alizarin Red S staining. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to evaluate the expression of (Toll-like receptor 4) TLR4, IL-6, IL-8, IL-1β, OPG, RUNX2 mRNA. It is shown that the mean diameter of nano-fibers is about 200 nm. The mean diameter of chitosan nano-particles is about 50 nm. The combination of chitosan nano-particles enhanced the mechanical properties of pure PLA nano-fibers. By adding a certain amount of chitosan nano-particles, it promoted cell adhesion. It also promoted the osteogenic differentiation of bone marrow stem cells (BMSCs) by elevating the expression of osteogenic marker genes such as BSP, Ocn, collagen I, and OPN and enhanced ECM mineralization. Nonetheless, it caused higher expression of inflammatory mediators and TLR4 of human periodontal ligament cells (hPDLCs). The combination of chitosan nano-particles enhanced the mechanical properties of pure PLA nano-fibers and increased its hydrophilicity. Pure PLA nano-fibers scaffold facilitated BMSCs proliferation. Adding an appropriate amount of chitosan nano-particles may promote its properties of cell proliferation

  8. Improvement of in vivo efficacy of recombinant human erythropoietin by encapsulation in PEG–PLA micelle

    Directory of Open Access Journals (Sweden)

    Shi YN

    2012-12-01

    Full Text Available Yanan Shi,1,2,* Wan Huang,1,* Rongcai Liang,1–3 Kaoxiang Sun,2,3 Fangxi Zhang,2,3 Wanhui Liu,2,3 Youxin Li1–31College of Life Science, Jilin University, Changchun, China; 2State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Co, Ltd, Yantai, China; 3School of Pharmacy, Yantai University, Yantai, China*These authors contributed equally to this workAbstract: To improve the pharmacokinetics and stability of recombinant human erythropoietin (rhEPO, rhEPO was successfully formulated into poly(ethylene glycol–poly(d,l-lactide (PEG–PLA di-block copolymeric micelles at diameters ranging from 60 to 200 nm with narrow polydispersity indices (PDIs; PDI < 0.3 and trace amount of protein aggregation. The zeta potential of the spherical micelles was in the range of −3.78 to 4.65 mV and the highest encapsulation efficiency of rhEPO in the PEG–PLA micelles was about 80%. In vitro release profiles indicated that the stability of rhEPO in the micelles was improved significantly and only a trace amount of aggregate was found. Pharmacokinetic studies in rats showed highly enhanced plasma retention time of the rhEPO-loaded PEG-PLA micelles in comparison with the native rhEPO group. Increased hemoglobin concentrations were also found in the rat study. Native polyacrylamide gel electrophoresis results demonstrated that rhEPO was successfully encapsulated into the micelles, which was stable in phosphate buffered saline with different pHs and concentrations of NaCl. Therefore, PEG–PLA micelles can be a potential protein drug delivery system.Keywords: rhEPO, PEG–PLA micelle, in vitro, pharmacokinetics, pharmacodynamics

  9. Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Stoleru, Elena; Dumitriu, Raluca Petronela [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania); Munteanu, Bogdanel Silvestru [“Al. I. Cuza” University, Faculty of Physics, 11 Carol I Blvd., 700506 Iasi (Romania); Zaharescu, Traian [INCDIE ICPE CA, Bucharest (Romania); Tănase, Elisabeta Elena; Mitelut, Amalia [Industrial Biotechnology Department, Faculty of Biotechnology – USAMV Bucharest (Romania); Ailiesei, Gabriela-Liliana [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania); Vasile, Cornelia, E-mail: cvasile@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania)

    2016-03-30

    Graphical abstract: - Highlights: • PLA requires functionalization prior to surface attaching chitosan. • Chitosan with different molecular weights was grafted onto PLA surface. • Antibacterial, antifungal, antioxidant PLA-based materials are obtained. • Nano-fibers coatings obtained by electrospinning of high molecular weight chitosan. - Abstract: A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by “grafting to” of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

  10. Facile Fabrication of 100% Bio-based and Degradable Ternary Cellulose/PHBV/PLA Composites

    Directory of Open Access Journals (Sweden)

    Tao Qiang

    2018-02-01

    Full Text Available Modifying bio-based degradable polymers such as polylactide (PLA and poly(hydroxybutyrate-co-hydroxyvalerate (PHBV with non-degradable agents will compromise the 100% degradability of their resultant composites. This work developed a facile and solvent-free route in order to fabricate 100% bio-based and degradable ternary cellulose/PHBV/PLA composite materials. The effects of ball milling on the physicochemical properties of pulp cellulose fibers, and the ball-milled cellulose particles on the morphology and mechanical properties of PHBV/PLA blends, were investigated experimentally and statistically. The results showed that more ball-milling time resulted in a smaller particle size and lower crystallinity by way of mechanical disintegration. Filling PHBV/PLA blends with the ball-milled celluloses dramatically increased the stiffness at all of the levels of particle size and filling content, and improved their elongation at the break and fracture work at certain levels of particle size and filling content. It was also found that the high filling content of the ball-milled cellulose particles was detrimental to the mechanical properties for the resultant composite materials. The ternary cellulose/PHBV/PLA composite materials have some potential applications, such as in packaging materials and automobile inner decoration parts. Furthermore, filling content contributes more to the variations of their mechanical properties than particle size does. Statistical analysis combined with experimental tests provide a new pathway to quantitatively evaluate the effects of multiple variables on a specific property, and figure out the dominant one for the resultant composite materials.

  11. Influence of Maleic Anhydride/Glycidyl Methacrylate Cografted Polylactic Acid on Properties of Wood Flour/PLA Composites

    Directory of Open Access Journals (Sweden)

    DU Jun

    2017-12-01

    Full Text Available Graft copolymers of PLA-g-MAH, PLA-g-GMA and PLA-co-MAH/GMA were prepared by means of melt grafting. The structure of the graft copolymers were characterized by FTIR.Wood flour/PLA composites were prepared by injection molding with three kinds of graft copolymers as compatibilizers, and the fractured morphology of composites was investigated by scanning electron microscope (SEM. Results show that there is no obvious phase interface between wood flour and PLA,which indicating the interfacial compatibility of wood flour/PLA composites is improved after adding different graft copolymers. The determination results of mechanical properties, processing flowability and dynamic rheological property of composites prepared with different graft copolymers reveal that, compared to the composite without compatibilizer, the tensile strength and impact strength of wood flour/PLA composites are increased by 9.54% and 7.23% respectively, and the equilibrium torque, shear heat, storage modulus and complex viscosity are all increased after adding maleic anhydride/glycidyl methacrylate cografted polylactic acid.

  12. Effect of platy and tubular nanoclays on behaviour of biodegradable PCL/PLA blend and related microfibrillar composites

    Science.gov (United States)

    Kelnar, Ivan; Kratochvíl, Jaroslav

    2016-05-01

    Blending of ductile poly(ɛ-caprolactone) (PCL) and rigid polylactic acid (PLA) is a promising way to tailor biodegradable materials with broad range of properties. But the mutual incompatibility of both polyesters leads to compromised behaviour only. Alternative to PCL/PLA blends is application of PLA in the form of short fibres, however, difficult dispergation of flexible fibres including their poor adhesion and limited processing is a significant restriction. More effective is in situ formation of polymeric fibre-reinforced materials using microfibrillar composites (MFC) concept based on melt- or cold-drawing of a polymer blend. Important advantage of MFC is efficient dispersion and bonding of in-situ formed reinforcing fibres This work deals with combination of structure-directing and reinforcing effects of montmorillonite (oMMT) and halloysite nanotubes (HNT) in the PCL/PLA 80/20 blend with in-situ formation of PLA fibrils in the PCL matrix. In the resulting microfibrillar composite, reinforcement by rigid PLA fibrils is combined with strengthening of both components by the nanofiller (NF). Moreover, PLA fibrils formation via melt-drawing is only possible after nanofiller addition due to favourable affecting of rheological parameters of the polymer components. The structure-properties relationship and complex effect of NF on microfibrillar composite performance, causing e.g., quite comparable parameters of both microfibrillar composites in spite of lower reinforcing effect of halloysite nanotubes on components, are discussed.

  13. A Functional Iron Oxide Nanoparticles Modified with PLA-PEG-DG as Tumor-Targeted MRI Contrast Agent.

    Science.gov (United States)

    Xiong, Fei; Hu, Ke; Yu, Haoli; Zhou, Lijun; Song, Lina; Zhang, Yu; Shan, Xiuhong; Liu, Jianping; Gu, Ning

    2017-08-01

    Tumor targeting could greatly promote the performance of magnetic nanomaterials as MRI (Magnetic Resonance Imaging) agent for tumor diagnosis. Herein, we reported a novel magnetic nanoparticle modified with PLA (poly lactic acid)-PEG (polyethylene glycol)-DG (D-glucosamine) as Tumor-targeted MRI Contrast Agent. In this work, we took use of the D-glucose passive targeting on tumor cells, combining it on PLA-PEG through amide reaction, and then wrapped the PLA-PEG-DG up to the Fe 3 O 4 @OA NPs. The stability and anti phagocytosis of Fe 3 O 4 @OA@PLA-PEG-DG was tested in vitro; the MRI efficiency and toxicity was also detected in vivo. These functional magnetic nanoparticles demonstrated good biocompatibility and stability both in vitro and in vivo. Cell experiments showed that Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles exist good anti phagocytosis and high targetability. In vivo MRI images showed that the contrast effect of Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles prevailed over the commercial non tumor-targeting magnetic nanomaterials MRI agent at a relatively low dose. The DG can validly enhance the tumor-targetting effect of Fe 3 O 4 @OA@PLA-PEG nanoparticle. Maybe MRI agents with DG can hold promise as tumor-targetting development in the future.

  14. Humoral and cellular immune responses to Yersinia pestis Pla antigen in humans immunized with live plague vaccine.

    Science.gov (United States)

    Feodorova, Valentina A; Lyapina, Anna M; Khizhnyakova, Maria A; Zaitsev, Sergey S; Sayapina, Lidiya V; Arseneva, Tatiana E; Trukhachev, Alexey L; Lebedeva, Svetlana A; Telepnev, Maxim V; Ulianova, Onega V; Lyapina, Elena P; Ulyanov, Sergey S; Motin, Vladimir L

    2018-06-01

    To establish correlates of human immunity to the live plague vaccine (LPV), we analyzed parameters of cellular and antibody response to the plasminogen activator Pla of Y. pestis. This outer membrane protease is an essential virulence factor that is steadily expressed by Y. pestis. PBMCs and sera were obtained from a cohort of naïve (n = 17) and LPV-vaccinated (n = 34) donors. Anti-Pla antibodies of different classes and IgG subclasses were determined by ELISA and immunoblotting. The analysis of antibody response was complicated with a strong reactivity of Pla with normal human sera. The linear Pla B-cell epitopes were mapped using a library of 15-mer overlapping peptides. Twelve peptides that reacted specifically with sera of vaccinated donors were found together with a major cross-reacting peptide IPNISPDSFTVAAST located at the N-terminus. PBMCs were stimulated with recombinant Pla followed by proliferative analysis and cytokine profiling. The T-cell recall response was pronounced in vaccinees less than a year post-immunization, and became Th17-polarized over time after many rounds of vaccination. The Pla protein can serve as a biomarker of successful vaccination with LPV. The diagnostic use of Pla will require elimination of cross-reactive parts of the antigen.

  15. Pulmonary venous flows reflect changes in left atrial hemodynamics during mitral balloon valvotomy.

    Science.gov (United States)

    Yalçin, Fatih; El-Amrousy, Mahmoud; Müderrisoğlu, Haldun; Korkmaz, Mehmet; Flachskampf, Frank; Tuzcu, Murat; Garcia, Mario G; Thomas, James D

    2002-01-01

    Patients with mitral stenosis have usually blunted pulmonary venous (PV) flow, because of decreased mitral valve area and diastolic dysfunction. The authors compared changes in Doppler PV velocities by using transesophageal echocardiography (TEE) against hemodynamics parameters before and after mitral balloon valvotomy to observe relevance of PV velocities and endsystolic left atrial (LA) pressure-volume relationship. In 25 patients (aged 35 +/- 17 years) with mitral stenosis in sinus rhythm, changes in LA pressure and volumes were compared with PV velocities before and after valvotomy. Mitral valve area, mitral gradients, and deceleration time were obtained. Mitral valve area and mitral gradients changed from 1 +/- 0.2 cm2 and 14.6 +/- 5.4 mmHg to 1.9 +/- 0.3 cm2 and 6.3 +/- 1.7 mmHg, respectively (pLA pressure were correlated with changes in S/D (r=0.57, pLA pressure-volume relationship were also correlated with changes in S/D (r=0.52, pLA pressure-volume relationship decreased after mitral balloon valvotomy, as a result of a large decrease in pressure. PV systolic/diastolic (S/D) waves ratio reflects endsystolic LA pressure-volume relationship and may be used as another indicator of successful valvotomy.

  16. Fabrication of nanofibrous scaffold using a PLA and hagfish thread keratin composite; its effect on cell adherence, growth, and osteoblast differentiation

    International Nuclear Information System (INIS)

    Kim, Beom-Su; Lee, Jun; Park, Ko Eun; Park, Won Ho

    2013-01-01

    Electrospinning is a useful method for the production of nanofibrous scaffolds in the field of tissue engineering. Keratin has been used as a biomaterial for electrospinning and can be used in a variety of biomedical applications because it is a natural protein, giving it the ability to improve cell affinity of scaffolds. In this study, keratin was extracted from hagfish slime thread (H-keratin) and blended with polylactic acid (PLA) polymer solution to construct a nanofibrous scaffold. Wool keratin (W-keratin) was used as a control for the comparison of morphological, physical, and biological properties. The results of Fourier transform infrared spectroscopy showed the presence of both W-keratin and H-keratin in the electrospun PLA/keratin. Observations with a scanning electron microscope revealed that PLA, PLA/W-keratin, and PLA/H-keratin had similar average diameters (∼800 nm). Cell attachment experiments showed that MG-63 cells adhered more rapidly and spread better onto PLA/H-keratin than onto the pure PLA or PLA/W-keratin. Cell proliferation assay, DNA content, live/dead, and alkaline phosphatase activity assays showed that PLA/H-keratin scaffolds could accelerate the viability, proliferation, and osteogenesis of MG-63 cells relative to pure PLA or PLA/W-keratin nanofibrous scaffolds. These findings suggest that H-keratin can improve cellular attraction and has great potential to be used as a biomaterial in bone tissue engineering. (paper)

  17. cPLA2a-evoked formation of arachidonic acid and lysophospholipids is required for exocytosis in mouse pancreatic ß-cells

    DEFF Research Database (Denmark)

    Juhl, Kirstine; Høy, Marianne; Olsen, Hervør L.

    2003-01-01

    Using capacitance measurements, we investigated the effects of intracellularly applied recombinant human cytosolic phospholipase A2 (cPLA2 ) and its lipolytic products arachidonic acid and lysophosphatidylcholine on Ca2+-dependent exocytosis in single mouse pancreatic -cells. cPLA2 dose dependently......–80 to 280–300. cPLA2 -stimulated exocytosis was antagonized by the specific cPLA2 inhibitor AACOCF3. Ca2+-evoked exocytosis was reduced by 40% in cells treated with AACOCF3 or an antisense oligonucleotide against cPLA2 . The action of cPLA2 was mimicked by a combination of arachidonic acid...... and lysophosphatidylcholine (470% stimulation) in which each compound alone doubled the exocytotic response. Priming of insulin-containing secretory granules has been reported to involve Cl- uptake through ClC-3 Cl- channels. Accordingly, the stimulatory action of cPLA2 was inhibited by the Cl- channel inhibitor DIDS...

  18. cPLA2alpha-evoked formation of arachidonic acid and lysophospholipids is required for exocytosis in mouse pancreatic beta-cells

    DEFF Research Database (Denmark)

    Juhl, Kirstine; Høy, Marianne; Olsen, Hervør L

    2003-01-01

    Using capacitance measurements, we investigated the effects of intracellularly applied recombinant human cytosolic phospholipase A2 (cPLA2alpha) and its lipolytic products arachidonic acid and lysophosphatidylcholine on Ca2+-dependent exocytosis in single mouse pancreatic beta-cells. cPLA2alpha...... from 70-80 to 280-300. cPLA2alpha-stimulated exocytosis was antagonized by the specific cPLA2 inhibitor AACOCF3. Ca2+-evoked exocytosis was reduced by 40% in cells treated with AACOCF3 or an antisense oligonucleotide against cPLA2alpha. The action of cPLA2alpha was mimicked by a combination...... of arachidonic acid and lysophosphatidylcholine (470% stimulation) in which each compound alone doubled the exocytotic response. Priming of insulin-containing secretory granules has been reported to involve Cl- uptake through ClC-3 Cl- channels. Accordingly, the stimulatory action of cPLA2alpha was inhibited...

  19. Numerical investigations of buoyancy-driven natural ventilation in a simple atrium building and its effect on the thermal comfort conditions

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2012-01-01

    In the present study use of solar-assisted buoyancy-driven natural ventilation in a simple atrium building is explored numerically with particular emphasis on the thermal comfort conditions in the building. Initially various geometric configurations of the atrium space were considered in order to investigate airflows and temperature distributions in the building using a validated computational fluid dynamics (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modelling approach with the SST-k–ω turbulence model and the Discrete Transfer Radiation Model (DTRM) was used for the investigations. The steady-state governing equations were solved using a commercial CFD solver FLUENT © . From the numerical results obtained, it was noted that an atrium space integrated with a solar chimney would be a relatively better option to be used in an atrium building. In the geometry selected, the performance of the building in response to various changes in design parameters was investigated. The produced airflows and temperature distributions were then used to evaluate indoor thermal comfort conditions in terms of the thermal comfort indices, i.e. the well-known predicted mean vote (PMV) index, its modifications especially for natural ventilation, predicted percent dissatisfied (PPD) index and Percent dissatisfied (PD) factor due to draft. It was found that the thermal conditions in the occupied areas of the building developed as a result of the use of solar-assisted buoyancy-driven ventilation for the particular values of the design parameters selected are mostly in the comfortable zone. Finally, it is demonstrated that the proposed methodology leads to reliable thermal comfort predictions, while the effect of various design variables on the performance of the building is easily recognized. - Highlights: ► Numerical investigations were carried for the use of buoyancy-driven displacement ventilation in a simple atrium building. ► Effect of various atrium

  20. ABO blood groups: A risk factor for left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation.

    Science.gov (United States)

    Fu, Yuan; Li, Kuibao; Yang, Xinchun

    2017-08-01

    Previous studies have identified ABO blood groups as predictors of thromboembolic diseases. In patients with atrial fibrillation (AF), however, potential association between ABO blood groups and the risk of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM) has not been established. This is a retrospective case-control study that included 125 consecutive patients with non-valvular atrial fibrillation (NVAF) plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 31 December 2016. The controls were selected randomly from 1072 NVAF without TM at a 1:2 ratio. Potential association between ABO blood groups and TM was analyzed using multivariate logistic regression analysis. The risk of TM was higher in patients with blood group A (33.6% vs. 20.2% in non-A blood groups, P=0.005). After adjusting for age, sex, oral anticoagulant use, AF type and duration, and relevant functional measures (e.g., NT-pro BNP level, left atrium diameter, and left ventricular ejection fraction), blood group A remained associated with an increased risk of TM (OR=2.99, 95% CI 1.4-6.388, P=0.005). Blood group A is an independent risk factor for TM in NVAF patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Giant congenital aneurysm of the appendix of the left auricle; an entity potentially lethal

    International Nuclear Information System (INIS)

    Perafan, Sergio; Ascione, Giovanny; Parra, Luis E; Jimenez, Luz S

    2004-01-01

    The case of a 22 years old female patient who at 16 years of age suffered a closed thoracic trauma during a car accident is reported. She underwent surgery under extra corporeal circulation with femoro-femoral cannulation with the diagnosis of rupture of the left atrium. a large aneurysm of the left auricle without evidence of heart trauma, pericardial leakage or hemo pericardium, was found. The surgeon decided not to perform surgery on the aneurysm and to withdraw the extra corporeal circulation, proceeding to suture the patient, who was released with the recommendation of performing additional studies in order to consider the handling of the aneurysm. Six years later she is sent to our institution with the diagnosis of cerebral embolism with left hemiparesis, and a giant partially thrombosed left auricle aneurysm. With a diagnosis of an embolizing partially thrombosed aneurysm of the left auricle she underwent surgery under extracorporeal circulation in order to resect it. The case with the intraoperative findings and the surgical technique are described. Different manifestations and expressions of this potentially lethal rare entity are detailed, concluding that it is imperative to resect surgically the aneurysm once it has been diagnosed

  2. A case of anemia with left atrial myxoma suspected as late effect of an atomic bomb

    International Nuclear Information System (INIS)

    Sugahara, Hiroko; Aosaki, Noboru; Kurita, Akira

    1980-01-01

    A 43 years old housewife with a history of exposure to an atomic bomb at 8 years old, recently developed anemia and palpitation. The laboratory data showed accelerated ESR, anemia (Hb 10.0 g/dl), and hyper γ-globulinemia. Despite the suspicion of late effect of atomic radiation, further examinations confirmed the diagnosis of left atrial myxoma. The echocardiographic studies revealed the decrease of diastolic descent rate, and multiple echos reflected from the tumor within the mitral orifice during diastole. Cardiac catheterization demonstrated remarkably high value of PCWP (V-wave 38 mmHg) and space filling defect moving from left atrium to left ventricle by cineangiography. Phonecardiographic studies were similar to mitral stenosis. After left atrial myxoma was removed, her symptoms and laboratory data including all noninvasive findings were improved. Therefore we suspected that her symptoms was related with left atrial myxoma rather than the late effect of atomic bomb exposure. We have discussed its significance and usefulness of noninvasive diagnostic approaches as well as whole body computed tomography in heart tumor. (author)

  3. Size of Left Cardiac Chambers Correlates with Cerebral Microembolic Load in Open Heart Operations

    Directory of Open Access Journals (Sweden)

    Elena Z. Golukhova

    2010-01-01

    Full Text Available Background. Microemboli are a widely recognized etiological factor of cerebral complications in cardiac surgery patients. The present study was aimed to determine if size of left cardiac chambers relates to cerebral microembolic load in open heart operations. Methods. Thirty patients participated in the study. Echocardiography was performed in 2-3 days before surgery. A transcranial Doppler system was used for registering intraoperative microemboli. Results. Preoperative left atrium and left ventricular end-systolic and end-diastolic sizes significantly correlated with intraoperative microembolic load (s=0.48, 0.57 and 0.53, s≺.01, resp.. The associations between left ventricular diameters and number of cerebral microemboli remained significant when cardiopulmonary bypass time was included as a covariate into the analysis. Conclusions. The present results demonstrate that increased size of left heart chambers is an influential risk factor for elevated cerebral microembolic load during open heart operations. Mini-invasive surgery and carbon dioxide insufflation into wound cavity may be considered as neuroprotective approaches in patients with high risk of cerebral microembolism.

  4. No Community Left Behind

    Science.gov (United States)

    Schlechty, Phillip C.

    2008-01-01

    The debate over the reauthorization of No Child Left Behind (NCLB) generally overlooks--or looks past--what may be the most fundamental flaw in that legislation. As the law is now written, decisions regarding what the young should know and be able to do are removed from the hands of parents and local community leaders and turned over to officials…

  5. The Children Left Behind

    Science.gov (United States)

    Gillard, Sarah A.; Gillard, Sharlett

    2012-01-01

    This article explores some of the deficits in our educational system in regard to non-hearing students. It has become agonizingly clear that non-hearing students are being left out of the gallant sweep to enrich our children's educations. The big five areas of literacy, at best, present unique challenges for non-hearing students and, in some…

  6. Left atrial appendage occlusion

    Directory of Open Access Journals (Sweden)

    Ahmad Mirdamadi

    2013-01-01

    Full Text Available Left atrial appendage (LAA occlusion is a treatment strategy to prevent blood clot formation in atrial appendage. Although, LAA occlusion usually was done by catheter-based techniques, especially percutaneous trans-luminal mitral commissurotomy (PTMC, it can be done during closed and open mitral valve commissurotomy (CMVC, OMVC and mitral valve replacement (MVR too. Nowadays, PTMC is performed as an optimal management of severe mitral stenosis (MS and many patients currently are treated by PTMC instead of previous surgical methods. One of the most important contraindications of PTMC is presence of clot in LAA. So, each patient who suffers of severe MS is evaluated by Trans-Esophageal Echocardiogram to rule out thrombus in LAA before PTMC. At open heart surgery, replacement of the mitral valve was performed for 49-year-old woman. Also, left atrial appendage occlusion was done during surgery. Immediately after surgery, echocardiography demonstrates an echo imitated the presence of a thrombus in left atrial appendage area, although there was not any evidence of thrombus in pre-pump TEE. We can conclude from this case report that when we suspect of thrombus of left atrial, we should obtain exact history of previous surgery of mitral valve to avoid misdiagnosis clotted LAA, instead of obliterated LAA. Consequently, it can prevent additional evaluations and treatments such as oral anticoagulation and exclusion or postponing surgeries including PTMC.

  7. The Leu33/Pro polymorphism (PlA1/PlA2) of the glycoprotein IIIa (GPIIIa) receptor is not related to myocardial infarction in the ECTIM Study. Etude Cas-Temoins de l'Infarctus du Myocarde.

    Science.gov (United States)

    Herrmann, S M; Poirier, O; Marques-Vidal, P; Evans, A; Arveiler, D; Luc, G; Emmerich, J; Cambien, F

    1997-06-01

    The GPIIb/IIIa receptor complex may contribute to acute coronary syndromes by mediating platelet aggregation. The Leu33/Pro polymorphism (PlA1/PlA2) of the GPIIIa has recently been shown to be associated with CHD in a small case-control study. We have investigated this polymorphism in a large multicenter study of patients with myocardial infarction and controls and found no difference in the distribution of allele and genotype frequencies between cases and controls.

  8. Hypoplastic left heart syndrome

    Directory of Open Access Journals (Sweden)

    Thiagarajan Ravi

    2007-05-01

    Full Text Available Abstract Hypoplastic left heart syndrome(HLHS refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch. Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision

  9. Left atrial accessory appendages, diverticula, and left-sided septal pouch in multi-slice computed tomography. Association with atrial fibrillation and cerebrovascular accidents.

    Science.gov (United States)

    Hołda, Mateusz K; Koziej, Mateusz; Wszołek, Karolina; Pawlik, Wiesław; Krawczyk-Ożóg, Agata; Sorysz, Danuta; Łoboda, Piotr; Kuźma, Katarzyna; Kuniewicz, Marcin; Lelakowski, Jacek; Dudek, Dariusz; Klimek-Piotrowska, Wiesława

    2017-10-01

    The aim of this study is to provide a morphometric description of the left-sided septal pouch (LSSP), left atrial accessory appendages, and diverticula using cardiac multi-slice computed tomography (MSCT) and to compare results between patient subgroups. Two hundred and ninety four patients (42.9% females) with a mean of 69.4±13.1years of age were investigated using MSCT. The presence of the LSSP, left atrial accessory appendages, and diverticula was evaluated. Multiple logistic regression analysis was performed to check whether the presence of additional left atrial structures is associated with increased risk of atrial fibrillation and cerebrovascular accidents. At least one additional left atrial structure was present in 51.7% of patients. A single LSSP, left atrial diverticulum, and accessory appendage were present in 35.7%, 16.0%, and 4.1% of patients, respectively. After adjusting for other risk factors via multiple logistic regression, patients with LSSP are more likely to have atrial fibrillation (OR=2.00, 95% CI=1.14-3.48, p=0.01). The presence of a LSSP was found to be associated with an increased risk of transient ischemic attack using multiple logistic regression analysis after adjustment for other risk factors (OR=3.88, 95% CI=1.10-13.69, p=0.03). In conclusion LSSPs, accessory appendages, and diverticula are highly prevalent anatomic structures within the left atrium, which could be easily identified by MSCT. The presence of LSSP is associated with increased risk for atrial fibrillation and transient ischemic attack. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Right atrium positioning for exposure of right pulmonary veins during off-pump atrial fibrillation ablation.

    Science.gov (United States)

    Suwalski, Grzegorz; Emery, Robert; Mróz, Jakub; Kaczejko, Kamil; Gryszko, Leszek; Cwetsch, Andrzej; Skrobowski, Andrzej

    2017-06-01

    Concomitant surgical ablation of atrial fibrillation (AF) is recommended for patients undergoing off-pump coronary revascularization in the presence of this arrhythmia. Achievement of optimal visualization of pulmonary veins while maintaining stable haemodynamic conditions is crucial for proper completion of the ablation procedure. This study evaluates the safety and feasibility of right atrial positioning using a suction-based cardiac positioner as opposed to compressive manoeuvres for exposure during off-pump surgical ablation for AF. Thirty-four consecutive patients underwent pulmonary vein isolation, ganglionated plexi ablation and left atrial appendage occlusion during off-pump coronary artery bypass grafting. Right atrial suction positioning was used to visualize right pulmonary veins. Safety and feasibility end points were analysed intraoperatively and in the early postoperative course. In all patients, right atrial positioning created optimal conditions to complete transverse and oblique sinus blunt dissection, correct placement of a bipolar ablation probe, detection and ablation of ganglionated plexi and conduction block assessment. In all patients, this entire right-sided ablation procedure was completed with a single exposure manoeuvre. Feasibility end points were achieved in all study patients. This report documents the safety and feasibility of right atrial exposure using a suction-based cardiac positioner to complete ablation for AF concomitant with off-pump coronary revascularization. This technique may be widely adopted to create stable haemodynamic conditions and optimal visualization of the right pulmonary veins. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  11. The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes.

    Science.gov (United States)

    Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

    2014-11-01

    The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect. PHMG derivatives introduced into PLA affected the activity of microbial hydrolases to a small extent. This means that the introduction of PHMG derivatives into PLA will not reduce its enzymatic biodegradation significantly. On the other hand, PHMG derivatives introduced into PLA strongly affected dehydrogenases activity in S. aureus than in E. coli.

  12. Mechanical performance evaluation of bionanocomposites with polymeric matrix of poly(lactic acid)-PLA and organo clay

    International Nuclear Information System (INIS)

    Cavalcanti, Shirley N.; Melo, Tomas J.A. de; Araujo, Edcleide M.; Oliveira, Akidauana D.A.; Lima, Jessica C.C.

    2011-01-01

    The aim of this study is to evaluate the influence of ethylene/methyl acrylate (EMA) and ethylene/glycidyl methacrylate (E-GMA) copolymers and organoclay on the mechanical properties of polymer PLA-poly (lactic acid), from the system PLA / organoclay. The clay was organophilized with the ionic surfactant praepagem and the mixtures were prepared in a modular twin screw extruder. The behavior of bionanocomposites was evaluated by tensile and impact tests. The results of FTIR and DR-X indicated that the process was efficient organophilization. The mechanical properties showed that the elastic modulus and tensile strength of bionanocomposites obtained decreased compared to PLA. On the other hand there was a gain for resistance to impact, for all systems except for system PLA/OMMT. (author)

  13. Biodegradable packaging materials conception based on starch and polylactic acid (PLA) reinforced with cellulose.

    Science.gov (United States)

    Masmoudi, Fatma; Bessadok, Atef; Dammak, Mohamed; Jaziri, Mohamed; Ammar, Emna

    2016-10-01

    The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.

  14. Ductile-brittle transition behaviour of PLA/o-MMT films during the physical aging process

    Directory of Open Access Journals (Sweden)

    M. Ll. Maspoch

    2015-03-01

    Full Text Available The ductile-brittle transition behaviour of organo modified montmorillonite-based Poly(lactic acid films (PLA/o-MMT was analysed using the Essential Work of Fracture (EWF methodology, Small Punch Tests (SPT and Enthalpy relaxation analysis. While the EWF methodology could only be applied successfully to de-aged samples, small punch test (SPT was revealed as more effective for a mechanical characterization during the transient behaviour from ductile to brittle. According to differential scanning calorimetry (DSC results, physical aging at 30°C of PLA/o-MMT samples exhibited slower enthalpy relaxation kinetics as compared to the pristine polymer. Although all samples exhibited an equivalent thermodynamic state after being stored one week at 30°C, significant differences were observed in the mechanical performances. These changes could be attributed to the toughening mechanisms promoted by o-MMT.

  15. Left ventricular approach for recording His bundle potential in man.

    Science.gov (United States)

    Lee, Y S; Lien, W P

    1975-06-01

    The electrical potentials of the His bundle (HB) were recorded from the left ventricular endocardial surface in 28 patients ranging from 16 to 63 years of age. In 14 of the patients the left bundle branch (LB) potentials were also obtained. Placement of a bipolar electrode catheter tip toward the interventricular septum, right at and also 1 to 2 cm below the aortic valve, resulted in stable recordings of both potentials in successive cardiac cycles even at performing atrial or HB pacing from the right heart. The following intervals were measured in milliseconds (msec): P-A, A-H, H, H-V, LB, and LB-V. The average values in 12 patients (average age 26 plus or minus 7 years and average heart rate 90 plus or minus 16 beats per minute) with normal A-V conduction were as follows: P-A 28 plus or minus 7, A-H 76 plus or minus 16, H 19 plus or minus 3 and H-V 45 plus or minus 6 msec. The average values for LB and LB-V in 10 of these 12 patients were 15 plus or minus 3 and 25 plus or minus 3 msec respectively. Validation of the His bundle electrogram (HBE) from the left ventricular endocardial surface was based on simultaneous recordings of the intracardiac electrograms from both left and right sides of the heart in 18 patients. The individual average values for the intervals obtained from both sides of the heart in these patients were statistically not different, except that the H potential was slightly longer in duration fr m the left heart (P equals 0.05). Among these, 16 showed simultaneous onset of the H potentials, and the LB-V and RB-V conduction times from comparable points were almost the same. Indications for the left sided electro-physiologic studies include the following situations: (a) inability to record H from the right of the heart; (b) giant right atrium; and (c) possibly during atrial fibrillation.

  16. Improvement in autologous human fat transplant survival with SVF plus VEGF-PLA nano-sustained release microspheres.

    Science.gov (United States)

    Li, Liqun; Pan, Shengsheng; Ni, Binting; Lin, Yuanshao

    2014-08-01

    Early neovascularization is important for autologous fat transplant survival. SVF cells are ideal seed cells. Both vascular endothelial growth factor (VEGF) and SVF cells can promote neovascularization. However, the half-life (about 50 min) of VEGF is too short to sustain an adequate local concentration. We have investigated whether VEGF-polylactic acid (PLA) nano-sustained release microspheres plus SVF cells can improve neovascularization and survival of transplanted fat tissues. SVF cells were harvested and constructed VEGF-PLA nano-sustained release microspheres in vitro. Human fat tissues was mixed with SVF cells plus VEGF-PLA, SVF cells alone or Dulbecco's modified Eagle's medium as the control. These three mixtures were injected into random sites in 18 nude mice. Two months later, the transplants were weighed and examined histologically; and capillaries were counted to quantify neovascularization. Hematoxylin-eosin (HE) and anti-VEGF stains were applied to reveal cell infiltration. The mean wet weight of fat in the SVF plus VEGF-PLA, SVF alone, and control transplants were 0.18 ± 0.013 g, 0.16 ± 0.015 g, and 0.071 ± 0.12 g, respectively; the differences between groups were statistically significant. More vessels were present in the SVF plus VEGF-PLA transplants than in the other two types. Transplants mixed with SVF cells also had an acceptable density of capillaries. Histological analysis revealed that both the SVF plus VEGF-PLA and SVF alone transplants, but not the control transplants, were composed of adipose tissue, and had less fat necrosis and less fibrosis than control specimens. SVF plus VEGF-PLA transplants had significantly greater capillary density and VEGF expression than the other two transplant groups. Thus transplanted fat tissue survival and quality can be enhanced by the addition of VEGF-PLA nano-sustained release microspheres plus SVF cells. © 2014 International Federation for Cell Biology.

  17. Generation of N-Acylphosphatidylethanolamine by Members of the Phospholipase A/Acyltransferase (PLA/AT) Family*

    Science.gov (United States)

    Uyama, Toru; Ikematsu, Natsuki; Inoue, Manami; Shinohara, Naoki; Jin, Xing-Hua; Tsuboi, Kazuhito; Tonai, Takeharu; Tokumura, Akira; Ueda, Natsuo

    2012-01-01

    Bioactive N-acylethanolamines (NAEs), including N-palmitoylethanolamine, N-oleoylethanolamine, and N-arachidonoylethanolamine (anandamide), are formed from membrane glycerophospholipids in animal tissues. The pathway is initiated by N-acylation of phosphatidylethanolamine to form N-acylphosphatidylethanolamine (NAPE). Despite the physiological importance of this reaction, the enzyme responsible, N-acyltransferase, remains molecularly uncharacterized. We recently demonstrated that all five members of the HRAS-like suppressor tumor family are phospholipid-metabolizing enzymes with N-acyltransferase activity and are renamed HRASLS1–5 as phospholipase A/acyltransferase (PLA/AT)-1–5. However, it was poorly understood whether these proteins were involved in the formation of NAPE in living cells. In the present studies, we first show that COS-7 cells transiently expressing recombinant PLA/AT-1, -2, -4, or -5, and HEK293 cells stably expressing PLA/AT-2 generated significant amounts of [14C]NAPE and [14C]NAE when cells were metabolically labeled with [14C]ethanolamine. Second, as analyzed by liquid chromatography-tandem mass spectrometry, the stable expression of PLA/AT-2 in cells remarkably increased endogenous levels of NAPEs and NAEs with various N-acyl species. Third, when NAPE-hydrolyzing phospholipase D was additionally expressed in PLA/AT-2-expressing cells, accumulating NAPE was efficiently converted to NAE. We also found that PLA/AT-2 was partly responsible for NAPE formation in HeLa cells that endogenously express PLA/AT-2. These results suggest that PLA/AT family proteins may produce NAPEs serving as precursors of bioactive NAEs in vivo. PMID:22825852

  18. Three-Dimensional Printing as an Interdisciplinary Communication Tool: Preparing for Removal of a Giant Renal Tumor and Atrium Neoplastic Mass.

    Science.gov (United States)

    Golab, Adam; Slojewski, Marcin; Brykczynski, Miroslaw; Lukowiak, Magdalena; Boehlke, Marek; Matias, Daniel; Smektala, Tomasz

    2016-08-22

    Three-dimensional (3D) printing involves preparing 3D objects from a digital model. These models can be used to plan and practice surgery. We used 3D printing to plan for a rare complicated surgery involving the removal of a renal tumor and neoplastic mass, which reached the heart atrium. A printed kidney model was an essential element of communication for physicians with different specializations.

  19. Adrenocortical carcinoma with extension to the inferior vena cava and right atrium: 20-month-old girl with TP53 mutation

    Directory of Open Access Journals (Sweden)

    Terry L. Levin, MD

    2015-01-01

    Full Text Available A 20-month-old female presented with respiratory distress and a right adrenal mass extending into the inferior vena cava and right atrium. The mass was initially thought to be neuroblastoma. Pathology later revealed adrenocortical carcinoma. Inferior vena cava extension is far more common in adrenocortical carcinoma than neuroblastoma, and its presence should prompt clinical and laboratory evaluation for an adrenocortical tumor. The genetic findings in TP53 associated with this disease are discussed.

  20. 3D-printed scaffolds based on PLA/HA nanocomposites for trabecular bone reconstruction

    International Nuclear Information System (INIS)

    Niaza, K V; Senatov, F S; Kaloshkin, S D; Maksimkin, A V; Chukov, D I

    2016-01-01

    In the present work porous PLA scaffolds filled with micro- and nano- HA were studied. Both composites with micro- and nano-HA were obtained by extrusion in the same conditions. Scaffolds were obtained by 3D-printing by fused filament fabrication method. Structure of porous scaffolds was pre-modeled by computer software. Compression and three - point flexural tests were used to study mechanical properties of the scaffolds. (paper)

  1. Blending Novatein{sup ®} thermoplastic protein with PLA for carbon dioxide assisted batch foaming

    Energy Technology Data Exchange (ETDEWEB)

    Walallavita, Anuradha, E-mail: asw15@students.waikato.ac.nz; Verbeek, Casparus J. R., E-mail: jverbeek@waikato.ac.nz; Lay, Mark, E-mail: mclay@waikato.ac.nz [University of Waikato, Hamilton 3240 (New Zealand)

    2016-03-09

    The convenience of polymeric foams has led to their widespread utilisation in everyday life. However, disposal of synthetic petroleum-derived foams has had a detrimental effect on the environment which needs to be addressed. This study uses a clean and sustainable approach to investigate the foaming capability of a blend of two biodegradable polymers, polylactic acid (PLA) and Novatein® Thermoplastic Protein (NTP). PLA, derived from corn starch, can successfully be foamed using a batch technique developed by the Biopolymer Network Ltd. NTP is a patented formulation of bloodmeal and chemical additives which can be extruded and injection moulded similar to other thermoplastics. However, foaming NTP is a new area of study and its interaction with blowing agents in the batch process is entirely unknown. Subcritical and supercritical carbon dioxide have been examined individually in two uniquely designed pressure vessels to foam various compositions of NTP-PLA blends. Foamed material were characterised in terms of expansion ratio, cell size, and cellular morphology in order to study how the composition of NTP-PLA affects foaming with carbon dioxide. It was found that blends with 5 wt. % NTP foamed using subcritical CO{sub 2} expanded up to 11 times due to heterogeneous nucleation. Morphology analysis using scanning electron microscopy showed that foams blown with supercritical CO{sub 2} had a finer cell structure with consistent cell size, whereas, foams blown with subcritical CO{sub 2} ranged in cell size and showed cell wall rupture. Ultimately, this research would contribute to the production of a biodegradable foam material to be used in packaging applications, thereby adding to the application potential of NTP.

  2. Poly(lactic acid) (PLA) Based Tear Resistant and Biodegradable Flexible Films by Blown Film Extrusion

    OpenAIRE

    Norma Mallegni; Thanh Vu Phuong; Maria-Beatrice Coltelli; Patrizia Cinelli; Andrea Lazzeri

    2018-01-01

    Poly(lactic acid) (PLA) was melt mixed in a laboratory extruder with poly(butylene adipate-co-terephthalate) (PBAT) and poly(butylene succinate) (PBS) in the presence of polypropylene glycol di glycidyl ether (EJ400) that acted as both plasticizer and compatibilizer. The process was then scaled up in a semi-industrial extruder preparing pellets having different content of a nucleating agent (LAK). All of the formulations could be processed by blowing extrusion and the obtained films showed me...

  3. Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure

    OpenAIRE

    Michael Arthur Cuiffo; Jeffrey Snyder; Alicia M. Elliott; Nicholas Romero; Sandhiya Kannan; Gary P. Halada

    2017-01-01

    Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and pho...

  4. 3D-printed scaffolds based on PLA/HA nanocomposites for trabecular bone reconstruction

    Science.gov (United States)

    Niaza, K. V.; Senatov, F. S.; Kaloshkin, S. D.; Maksimkin, A. V.; Chukov, D. I.

    2016-08-01

    In the present work porous PLA scaffolds filled with micro- and nano- HA were studied. Both composites with micro- and nano-HA were obtained by extrusion in the same conditions. Scaffolds were obtained by 3D-printing by fused filament fabrication method. Structure of porous scaffolds was pre-modeled by computer software. Compression and three - point flexural tests were used to study mechanical properties of the scaffolds.

  5. Platanus pollen allergen, Pla a 1: quantification in the atmosphere and influence on a sensitizing population.

    Science.gov (United States)

    Fernández-González, D; González-Parrado, Z; Vega-Maray, A M; Valencia-Barrera, R M; Camazón-Izquierdo, B; De Nuntiis, P; Mandrioli, P

    2010-11-01

    The allergic response in susceptible patients does not always coincide with the presence and magnitude of airborne pollen counts. The prevalence of allergy to Platanus is currently moderate, although the percentage of monosensitized patients is low. This hinders accurate interpretation of the relationship between the amount of pollen inhaled and the patient's symptoms. This study aims to investigate the relationship between the atmospheric concentration pattern of Pla a 1 aeroallergen and the Platanus pollen. The pollen sampling was carried out using a Hirst-type volumetric trap (Burkard(©) ) for pollen grains and a Burkard Cyclone sampler (Burkard(©) ) for Pla a 1 allergen. Serum-specific IgE levels to Acer sp., Artemisia vulgaris, Betula alba, Chenopodium album, Cupressus arizonica, Cynodon dactylon, Fraxinus excelsior, Lolium perenne, Pinus sp., Plantago lanceolata, Platanus acerifolia, Populus sp., Quercus ilex and Taraxacum officinale allergens were determined using the EAST System (Hytec specific IgE EIA kit; Hycor Biomedical, Kassel, Germany). The aerobiological dynamics of Platanus pollen grains and Pla a 1 differed considerably, particularly during the Platanus pollination period. Of the 118 subjects tested, sera from 34 contained specific IgE to Platanus pollen and all of them had specific IgE to other pollen types. The presence of the aeroallergen Pla a 1 in the atmosphere appears to be independent of Platanus pollen counts over the same period, which may be contributing to allergic symptoms and sensitization. The number of polysensitized patients displaying allergy to Platanus suggested that allergic symptoms were caused by co-sensitization or cross-reactivity involving a number of allergenic particles. © 2010 Blackwell Publishing Ltd.

  6. 3D-Printed ABS and PLA Scaffolds for Cartilage and Nucleus Pulposus Tissue Regeneration

    OpenAIRE

    Rosenzweig, Derek H.; Carelli, Eric; Steffen, Thomas; Jarzem, Peter; Haglund, Lisbet

    2015-01-01

    Painful degeneration of soft tissues accounts for high socioeconomic costs. Tissue engineering aims to provide biomimetics recapitulating native tissues. Biocompatible thermoplastics for 3D printing can generate high-resolution structures resembling tissue extracellular matrix. Large-pore 3D-printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) scaffolds were compared for cell ingrowth, viability, and tissue generation. Primary articular chondrocytes and nucleus pulposus (N...

  7. Diadenosine pentaphosphate affects electrical activity in guinea pig atrium via activation of potassium acetylcholine-dependent inward rectifier.

    Science.gov (United States)

    Abramochkin, Denis V; Karimova, Viktoria M; Filatova, Tatiana S; Kamkin, Andre

    2017-07-01

    Diadenosine pentaphosphate (Ap5A) belongs to the family of diadenosine polyphosphates, endogenously produced compounds that affect vascular tone and cardiac performance when released from platelets. The previous findings indicate that Ap5A shortens action potentials (APs) in rat myocardium via activation of purine P2 receptors. The present study demonstrates alternative mechanism of Ap5A electrophysiological effects found in guinea pig myocardium. Ap5A (10 -4  M) shortens APs in guinea pig working atrial myocardium and slows down pacemaker activity in the sinoatrial node. P1 receptors antagonist DPCPX (10 -7  M) or selective GIRK channels blocker tertiapin (10 -6  M) completely abolished all Ap5A effects, while P2 blocker PPADS (10 -4  M) was ineffective. Patch-clamp experiments revealed potassium inward rectifier current activated by Ap5A in guinea pig atrial myocytes. The current was abolished by DPCPX or tertiapin and therefore was considered as potassium acetylcholine-dependent inward rectifier (I KACh ). Thus, unlike rat, in guinea pig atrium Ap5A produces activation of P1 receptors and subsequent opening of KACh channels leading to negative effects on cardiac electrical activity.

  8. Tough and strong porous bioactive glass-PLA composites for structural bone repair.

    Science.gov (United States)

    Xiao, Wei; Zaeem, Mohsen Asle; Li, Guangda; Bal, B Sonny; Rahaman, Mohamed N

    2017-08-01

    Bioactive glass scaffolds have been used to heal small contained bone defects but their application to repairing structural bone is limited by concerns about their mechanical reliability. In the present study, the addition of an adherent polymer layer to the external surface of strong porous bioactive glass (13-93) scaffolds was investigated to improve their toughness. Finite element modeling (FEM) of the flexural mechanical response of beams composed of a porous glass and an adherent polymer layer predicted a reduction in the tensile stress in the glass with increasing thickness and elastic modulus of the polymer layer. Mechanical testing of composites with structures similar to the models, formed from 13-93 glass and polylactic acid (PLA), showed trends predicted by the FEM simulations but the observed effects were considerably more dramatic. A PLA layer of thickness -400 µm, equal to -12.5% of the scaffold thickness, increased the load-bearing capacity of the scaffold in four-point bending by ~50%. The work of fracture increased by more than 10,000%, resulting in a non-brittle mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture shown to be conducive to bone infiltration, could provide optimal implants for healing structural bone defects.

  9. Manufacture of Partially Biodegradable Composite Materials Based on PLA-Tires Powder: Process and Characterization

    Directory of Open Access Journals (Sweden)

    Carlos Rolando Rios-Soberanis

    2013-01-01

    Full Text Available This research work focuses on the processability and mechanical characterization of blends of polylactic acid (PLA and tire (elastomeric part. Wasted tires used as filler in the PLA matrix were reduced by two different processes (thermal shock and pyrolysis in order to acquire the solid residuals in powder to be characterized and compared. Elastomeric solids obtained from scraped tires were used as filler in the PLA matrix and mixed in a Brabender 60 cc mixer at different concentrations ranging from 0% to 60% of filler volume fraction. The blend was laminated, and then samples were obtained in order to undertake mechanical properties at tension and Izod impact tests. A fully detailed analysis on the solid powders by Differential Scanning Calorimeter (DSC, thermogravimetric analysis (TGA, infrared analysis (IR, and scanning electron microscopy analysis (SEM identified them as a rich source of carbon. Blends were characterized thermally and mechanically showing a direct effect due to the tire nature (thermoset rubber and concentration. Fracture mechanisms were also identified.

  10. PLA-b-PEG/magnetite hyperthermic agent prepared by Ugi four component condensation

    Directory of Open Access Journals (Sweden)

    L. P. Icart

    2016-03-01

    Full Text Available Ugi four component condensation (UFCC, is an important tool for the synthesis of different types of bioconjugate species. In this study, a PLA-PEG/magnetite magnetic composite was prepared by a synthetic-route approach based on UFCC. In particular, poly(lactic acid (PLA was synthesized by autocatalytic polycondensation. Also, poly(ethyleneglycol bis-amine (bis-amine PEG was synthesized by two different methods: via carbonyldiimidazol (CDI/ethylenediamine (ED (75% yield and via chlorate monochlorated acetyl (CCA/ED (95% yield. All products were characterized by gel permeation chromatography (GPC, hydrogen-1 nuclear magnetic resonance (NMR 1H, Fourier transform infrared (FTIR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA. In addition, magnetite was prepared and modified to generate aldehyde groups which are also necessary for UFCC. This product was characterized by DSC, TGA, X-ray diffraction (XRD and magnetic force (MF techniques. Also, the magnetic composite PLA-PEG/magnetite was synthesized by UFCC. The calculated yield was equal to 80%. Furthermore, magnetic microspheres were prepared by the procedure of emulsion solvent-evaporation and characterized by scanning electron microscopy (SEM and magnetic induction hyperthermia (MIH. The main contribution of these results is to propose a new application for UFCC in the preparation of biomasked magnetic drug delivery systems able to improve the cancer treatment and even the welfare of the patients.

  11. Toughening of nanocelluose/PLA composites via bio-epoxy interaction: Mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangtao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bocharova, Vera [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tekinalp, Halil L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Cheng, Shiwang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisliuk, Alexander [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Alexei P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kunc, Vlastimil [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ozcan, Soydan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

    2017-11-07

    While PLA possesses modest to good strength and stiffness, broader application is hindered by its brittle nature. The aim of this study was to develop strong and tough polymeric materials from renewable biomaterials and understand the underlying interactions and mechanisms. Cellulose nanofibrils (CNFs) and epoxidized soybean oil (ESO) were compounded with poly(lactic acid) (PLA) to create a PLA-CNF-ESO tertiary nanocomposite system. Tensile and dynamic mechanical analyses were performed to see how variations in ESO and CNF content affect mechanical properties such as strength, modulus, ductility, and toughness. It was found that at low CNF levels (10 wt %) the addition of ESO can improve the ductility of the nanocomposites 5- to 10-fold with only slight losses in strength and modulus, while at higher CNF levels (20 and 30 wt %), ESO exhibited little effect on mechanical properties, possibly due to percolation of CNFs in the matrix, dominating stress transfer. Therefore, it is important to optimize CNF and ESO amounts in composites to achieve materials with both high strength and high toughness. As a result, efforts have been made to understand the underlying mechanisms of the mechanical behavior of one class of these composites via thermal, dynamic mechanical, morphological, and Raman analyses.

  12. The Processing Design of Jute Spun Yarn/PLA Braided Composite by Pultrusion Molding

    Directory of Open Access Journals (Sweden)

    Anin Memon

    2013-01-01

    Full Text Available Prevalently, the light has been shed on the green composite from the viewpoint of environmental protection. Jute fibers are natural fibers superior due to light weight, low cost, and being environmentally friendly corresponding to the green composite materials. Meticulously, fibers of polylactic acid (PLA thermoplastic biopolymer were used as the resin fibers. In this study, the fabrication of tubular jute spun yarn/PLA braided composite by pultrusion molding was presented. The intermediate materials were prepared by commingled technique. The braiding technique manufactured preform which had jute fiber diagonally oriented at certain angles with the glass fiber inserted into the braiding yarns along the longitudinal direction. The braided preforms were pulled through a heated die where the consolidation flow took place due to reduced matrix viscosity and pressure. The pultrusion experiments were done with jute/PLA commingled yarns and combined with glass fiber yarns to fabricate the tubular composite. Impregnation quality was evaluated by microscope observation of the pultruded cross-sections. The flexural mechanical properties of the pultruded were measured by four-point bending test.

  13. A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET and Polylactic Acid (PLA

    Directory of Open Access Journals (Sweden)

    Georg Steinkellner

    2012-02-01

    Full Text Available A new esterase from Thermobifida halotolerans (Thh_Est was cloned and expressed in E. coli and investigated for surface hydrolysis of polylactic acid (PLA and polyethylene terephthalate (PET. Thh_Est is a member of the serine hydrolases superfamily containing the -GxSxG- motif with 85–87% homology to an esterase from T. alba, to an acetylxylan esterase from T. fusca and to various Thermobifida cutinases. Thh_Est hydrolyzed the PET model substrate bis(benzoyloxyethylterephthalate and PET releasing terephthalic acid and mono-(2-hydroxyethyl terephthalate in comparable amounts (19.8 and 21.5 mmol/mol of enzyme while no higher oligomers like bis-(2-hydroxyethyl terephthalate were detected. Similarly, PLA was hydrolyzed as indicated by the release of lactic acid. Enzymatic surface hydrolysis of PET and PLA led to a strong hydrophilicity increase, as quantified with a WCA decrease from 90.8° and 75.5° to 50.4° and to a complete spread of the water drop on the surface, respectively.

  14. Role of Polysaccharides on Mechanical and Adhesion Properties of Flax Fibres in Flax/PLA Biocomposite

    Directory of Open Access Journals (Sweden)

    Gijo Raj

    2011-01-01

    Full Text Available The effect of alkali and enzymatic treatments on flax fibre morphology, mechanical, and adhesion properties was investigated. The multilength scale analysis allows for the correlation of the fibre's morphological changes induced by the treatments with mechanical properties to better explain the adherence properties between flax and PLA. The atomic force microscopy (AFM images revealed the removal of primary layers, upon treatments, down to cellulose microfibrils present in the secondary layers. The variation in mechanical properties was found to be dependent, apart from the crystalline content, on interaction between cellulose microfibrils and encrusting polysaccharides, pectins and hemicelluloses, in the secondary layers. Finally, microbond tests between the modified fibres and PLA emphasize the important role of the outer fibre's surface on the overall composite properties. It was observed here that gentle treatments of the fibres, down to the oriented microfibrils, are favourable to a better adherence with a PLA drop. This paper highlights the important role of amorphous polymers, hemicellulose and pectin, in the optimisation of the adhesion and mechanical properties of flax fibres in the biocomposite.

  15. The effect of the stretching of PLA extruded films on their crystallinity and gas barrier properties

    Science.gov (United States)

    Guinault, A.; Menary, G. H.; Courgneau, C.; Griffith, D.; Ducruet, V.; Miri, V.; Sollogoub, C.

    2011-05-01

    Driven by environmental concerns, new polymers based on renewable resources are arriving on the market to replace conventional polymers, obtained from petroleum, for different applications like food packaging. One of the most prominent polymers among these materials is poly(lactic acid) (PLA), a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the USA) or sugarcanes (in the rest of the world). However this polymer presents different disadvantages and especially low gas barrier properties [1]. Thermal crystallization can be used to increase its gas barrier properties but long times are necessary [2] and are not compatible with an industrial process. Another way to increase the gas barrier properties consists in stretching the film in order to increase its crystallinity and so its diffusion coefficient. We have prepared stretched PLA films with different stretch ratio and we have studied the effect of the stretching parameters on the gas barrier properties of PLA films. Finally we compared this process with the isothermal crystallization process by taking into account the crystallinity degree and the crystalline morphology.

  16. 3D-Printed ABS and PLA Scaffolds for Cartilage and Nucleus Pulposus Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Derek H. Rosenzweig

    2015-07-01

    Full Text Available Painful degeneration of soft tissues accounts for high socioeconomic costs. Tissue engineering aims to provide biomimetics recapitulating native tissues. Biocompatible thermoplastics for 3D printing can generate high-resolution structures resembling tissue extracellular matrix. Large-pore 3D-printed acrylonitrile butadiene styrene (ABS and polylactic acid (PLA scaffolds were compared for cell ingrowth, viability, and tissue generation. Primary articular chondrocytes and nucleus pulposus (NP cells were cultured on ABS and PLA scaffolds for three weeks. Both cell types proliferated well, showed high viability, and produced ample amounts of proteoglycan and collagen type II on both scaffolds. NP generated more matrix than chondrocytes; however, no difference was observed between scaffold types. Mechanical testing revealed sustained scaffold stability. This study demonstrates that chondrocytes and NP cells can proliferate on both ABS and PLA scaffolds printed with a simplistic, inexpensive desktop 3D printer. Moreover, NP cells produced more proteoglycan than chondrocytes, irrespective of thermoplastic type, indicating that cells maintain individual phenotype over the three-week culture period. Future scaffold designs covering larger pore sizes and better mimicking native tissue structure combined with more flexible or resorbable materials may provide implantable constructs with the proper structure, function, and cellularity necessary for potential cartilage and disc tissue repair in vivo.

  17. 3D-Printed ABS and PLA Scaffolds for Cartilage and Nucleus Pulposus Tissue Regeneration.

    Science.gov (United States)

    Rosenzweig, Derek H; Carelli, Eric; Steffen, Thomas; Jarzem, Peter; Haglund, Lisbet

    2015-07-03

    Painful degeneration of soft tissues accounts for high socioeconomic costs. Tissue engineering aims to provide biomimetics recapitulating native tissues. Biocompatible thermoplastics for 3D printing can generate high-resolution structures resembling tissue extracellular matrix. Large-pore 3D-printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) scaffolds were compared for cell ingrowth, viability, and tissue generation. Primary articular chondrocytes and nucleus pulposus (NP) cells were cultured on ABS and PLA scaffolds for three weeks. Both cell types proliferated well, showed high viability, and produced ample amounts of proteoglycan and collagen type II on both scaffolds. NP generated more matrix than chondrocytes; however, no difference was observed between scaffold types. Mechanical testing revealed sustained scaffold stability. This study demonstrates that chondrocytes and NP cells can proliferate on both ABS and PLA scaffolds printed with a simplistic, inexpensive desktop 3D printer. Moreover, NP cells produced more proteoglycan than chondrocytes, irrespective of thermoplastic type, indicating that cells maintain individual phenotype over the three-week culture period. Future scaffold designs covering larger pore sizes and better mimicking native tissue structure combined with more flexible or resorbable materials may provide implantable constructs with the proper structure, function, and cellularity necessary for potential cartilage and disc tissue repair in vivo.

  18. Characterization and properties of acetylated nanocrystalline cellulose (aNC) reinforced polylactic acid (PLA) polymer

    Science.gov (United States)

    Kasa, Siti Norbaya; Omar, Mohd Firdaus; Ismail, Ismarul Nizam

    2017-12-01

    Nanocrystalline cellulose (NCC) was synthesized from banana stem through strong acid hydrolysis with measured length of approximately 287.0 ± 56.4 nm and diameter of 26.6 ± 4.8 nm. Modification of NCC was carried by acetylation reaction in order to increase the compatibility during reinforcement with polylactic acid (PLA) polymer. The reinforcing effect towards morphology, crystallinity, mechanical and thermal properties of bio-nanocomposites was investigated. Scanning Electron Microscope (SEM) micrograph reveals the uniform dispersion achieved at 1 %, 3 % and 5% aNC loading while agglomeration was found at 7 % aNC loading. Disappearance of crystallinity peak at 2θ = 22.7⁰ for low aNC loading during elemental analysis using X-Ray Diffraction (XRD) indicates the proper dispersion of aNC in PLA polymer. From the tensile test, 1 % aNC loading gives the highest mechanical properties of bio-nanocomposite film with 82.71 %, 118.7 % and 24.18 % increment in tensile strength, tensile modulus and elongation at break. However, 7 % aNC loading gives the highest increment in TGA of aNC-PLA nanocomposites which is from 310 °C to 320 °C.

  19. Synthesis and innovation of PLA/clay nanocomposite characterization againts to mechanical and thermal properties

    Science.gov (United States)

    Salim, S.; Agusnar, H.; Wirjosentono, B.; Tamrin; Marpaung, H.; Rihayat, T.; Nurhanifa; Adriana

    2018-03-01

    Plastic polymer is one of the most dominant materials of daily human activities because of its multifunctional nature, light and strong and anti-corrosion so it is easy to apply in various equipment. Plastic is generally derived from petroleum material so it is nonbiodegradable. Therefore, this study aims to create a breakthrough of natural and biodegradable biodegradable plastic materials from plant starch (pisok kepok starch) with the help of 3 types of acid (HNO3, HCl and H2SO4) called Poly Lactid Acid (PLA). PLA is enhanced by mixing with a clay material with a variation of 1, 3 and 5% composition to form a PLA / Clay Nanocomposite material which is expected to have superior properties and resemble conventional plastics in general. Several types of characterization were performed to see the quality of the resulting material including tensile strength test with UTM tool, thermal endurance test with TGA tool, morphological structure test using SEM tool and additional test to see filler clay quality through X-RD tool. Based on the characterization of tensile and thermal test, 5B nanocomposite with addition of 5% clay and HCl acid aid showed the best tensile strength of 36 Mpa and the highest stability was 446,63 oC. Based on the results of morphological analysis of the best samples (5B) showed good interface ties. Meanwhile, based on the results of filler analysis, the opening of clay layer d-spacing occurred at 0.355 nm.

  20. In vivo evaluation of hybrid patches composed of PLA based copolymers and collagen/chondroitin sulfate for ligament tissue regeneration.

    Science.gov (United States)

    Pinese, Coline; Gagnieu, Christian; Nottelet, Benjamin; Rondot-Couzin, Capucine; Hunger, Sylvie; Coudane, Jean; Garric, Xavier

    2017-10-01

    Biomaterials for soft tissues regeneration should exhibit sufficient mechanical strength, demonstrating a mechanical behavior similar to natural tissues and should also promote tissues ingrowth. This study was aimed at developing new hybrid patches for ligament tissue regeneration by synergistic incorporation of a knitted structure of degradable polymer fibers to provide mechanical strength and of a biomimetic matrix to help injured tissues regeneration. PLA- Pluronic ® (PLA-P) and PLA-Tetronic ® (PLA-T) new copolymers were shaped as knitted patches and were associated with collagen I (Coll) and collagen I/chondroitine-sulfate (Coll CS) 3-dimensional matrices. In vitro study using ligamentocytes showed the beneficial effects of CS on ligamentocytes proliferation. Hybrid patches were then subcutaneously implanted in rats for 4 and 12 weeks. Despite degradation, patches retained strength to answer the mechanical physiological needs. Tissue integration capacity was assessed with histological studies. We showed that copolymers, associated with collagen and chondroitin sulfate sponge, exhibited very good tissue integration and allowed neotissue synthesis after 12 weeks in vivo. To conclude, PLA-P/CollCS and PLA-T/CollCS hybrid patches in terms of structure and composition give good hopes for tendon and ligament regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1778-1788, 2017. © 2016 Wiley Periodicals, Inc.

  1. Effect of thermoplastic polyurethane (TPU) on the thermal and mechanical properties of polylactic acid (PLA)/curcumin blends

    Science.gov (United States)

    Sharifah, I. S. S.; Adnan, M. D. A.; Nor Khairusshima, M. K.; Shaffiar, N. M.; Buys, Y. F.

    2018-01-01

    Polylactic acid (PLA) is known to be brittle by nature and thus limits the flexibility of the polymer. A possible solution to enhance the flexibility of PLA is to add a flexible polymeric based material such as thermoplastic polyurethane (TPU). In this study, 30-50 wt% of TPU was added into PLA/curcumin blends to improve its flexibility. Thermal analysis using differential scanning calorimetry shows that further additions of TPU at the expense of PLA did not affect the glass transition temperature, crystallisation temperature and melting temperature of the blends. Fibers of PLA/curcumin/TPU were successfully drawn and Single Fiber Tensile Test (SFTT) showed vast improvement in elongation at break. The initial addition of 30 wt% of TPU to the brittle PLA/curcumin composition causes a significant increase in elongation at break by 39 times and further additions at 50 wt %, the elongation at break increases by 105 times. However, with the increase in elongation, a decrease in strength and Young’s modulus was observed.

  2. Differential regulation of iPLA2beta splice variants by in vitro ischemia in C2C12 myotubes

    DEFF Research Database (Denmark)

    Poulsen, K. A.; Kolko, M.; Lambert, I. H.

    2006-01-01

    In this study we investigated the activity, expression and regulation of iPLA2 during ischemia in mouse C2C12 myotubes. Here, we show that in vitro ischemia, i.e. oxygen deprivation and glucose starvation, induces an iPLA2 activity that is totally reversed by siRNA knock down of iPLA2£], indicating...... preferential activation of iPLA2£]. The activity of the native iPLA2£] tetramer has in humans been proposed to be negatively regulated by interactions with catalytic inactive splice variants of the full-length protein. These variants, characterized by the presence exon 9a, have however not been identified...... of this transcript would be a C-terminally truncated î50 kDa protein lacking the catalytic site. qPCR indicated that, while the total iPLA2£] mRNA level in C2C12 myotubes increased weakly within 1-2 hours of in vitro ischemia, the transcript containing the mouse exon 9a was rapidly down regulated. In addition...

  3. Preparation and mechanical properties of PLA-PEG copolymers modified by radiation-induced crosslinking of low energy electron beams

    International Nuclear Information System (INIS)

    Peikai Miao; Wenrui Tang; Ke Zeng; Yan Tang; Yipeng Wang; Hongfei Zhou; Ke Zhou; Tao Liu; Gang Yang

    2007-01-01

    PLA-PEG copolymer is wildly applied in medical and pharmaceutical fields, but its mechanical properties are not so good, such as the tensile intensity and elongation at break. To improve these properties, PLA-PEG copolymers were synthesized and irradiated using low energy electron beams (EB) with various irradiation doses in the presence of 3 wt% polyfunctional monomer (triallylcyanurate, TAC) as crosslinking agent to introduce crosslinking between polymer chains. It was found that with the increase of the irradiation doses, the tensile intensity of the PLA-PEG increased, while the elongation at break decreased, the most optimal irradiation dose was 80 kGy, the tensile intensity was 12.5 MPa and 19.9 MPa, corresponding to the elongation at break of 282.8 % and 28.7% for PLA9-PEG6 and PLA11-PEG6, respectively. Meanwhile, the solvent resistance of crosslinked sample was improved obviously at this dose. The crosslinked PLA-PEG copolymer can be applied to packaging materials, tubes and so on. (Author)

  4. The Effect of UV Aging on Antimicrobial and Mechanical Properties of PLA Films with Incorporated Zinc Oxide Nanoparticles.

    Science.gov (United States)

    Mizielińska, Małgorzata; Kowalska, Urszula; Jarosz, Michał; Sumińska, Patrycja; Landercy, Nicolas; Duquesne, Emmanuel

    2018-04-18

    The aim of this study was to examine the influence of accelerated UV-aging on the activity against chosen microorganisms and the mechanical properties of poly-lactic acid (PLA) films enhanced with ZnO nanoparticles. The pure PLA films and tri-layered PLAZnO1%/PLA/PLAZnO1% films of 150 µm thickness were extruded. The samples were treated with UV-A and Q-SUN irradiation. After irradiation the antimicrobial activity and mechanical properties of the films were analyzed. The results of the study demonstrated that PLA films did not inhibit the growth of Staphylococcus aureus , Bacillus cereus , Escherichia coli , Bacillus atrophaeus , and Candida albicans cells. PLA films with incorporated zinc oxide nanoparticles decreased the number of analyzed microorganisms. Accelerated UV aging had no negative effect on the activity of the film containing nano-ZnO against Gram-positive bacteria, but it influenced the activity against Gram-negative cells and C. albicans . Q-SUN irradiation decreased the antimicrobial effect of films with incorporated nanoparticles against B. cereus . UV-A and Q-UV irradiation did not influence the mechanical properties of PLA films containing incorporated ZnO nanoparticles.

  5. Quantification of Pla or 3, a Platanus orientalis Allergen, Grown under Different Environmental Conditions, by Sandwich ELISA.

    Science.gov (United States)

    Sedghy, Farnaz; Sankian, Mojtaba; Moghadam, Maliheh; Varasteh, Abdol-Reza

    2016-10-01

    Platanus species are widely cultured around the world and considered an important cause of allergic reactions. In the present study, we developed a sandwich ELISA to quantify Pla or 3 allergen in P. orientalis pollen extracts grown near high-traffic roads and compared it to pollen extracts collected from rural areas as control. Pollen samples were collected from three polluted and two unpolluted sites in Mashhad, northeast Iran. Recombinant Pla or 3 was expressed and used for polyclonal antibody production in rabbit. A sandwich ELISA was developed and validated to quantify Pla or 3 levels in pollen extracts from the different sites. The coefficients of variation (CVs) for the intra- and inter- day assays were less than 5 and 18%, respectively. The working range of the standard curve was between 0.1 and 25 ng/ml, with the detection limit being 0.037 ng/ml. The recovery percentage was 88-106.4% at working concentrations from 0.31 to 26.5 ng/ml. Pla or 3 levels were significantly greater in pollens grown near high-traffic roads than in those grown in rural regions (p Pla or 3 in pollen extracts. Using this validated ELISA, we showed a substantial difference between the amounts of Pla or 3 in pollens grown in different environments. This finding should be considered in developing public policies to reduce traffic pollution, which leads to reduced allergic reactions in atopic subjects.

  6. Modifying an Active Compound’s Release Kinetic Using a Supercritical Impregnation Process to Incorporate an Active Agent into PLA Electrospun Mats

    Directory of Open Access Journals (Sweden)

    Carol López de Dicastillo

    2018-04-01

    Full Text Available The main objective of this work was to study the release of cinnamaldehyde (CIN from electrospun poly lactic acid (e-PLA mats obtained through two techniques: (i direct incorporation of active compound during the electrospinning process (e-PLA-CIN; and (ii supercritical carbon dioxide (scCO2 impregnation of CIN within electrospun PLA mats (e-PLA/CINimp. The development and characterization of both of these active electrospun mats were investigated with the main purpose of modifying the release kinetic of this active compound. Morphological, structural, and thermal properties of these materials were also studied, and control mats e-PLA and e- PLA CO 2 were developed in order to understand the effect of electrospinning and scCO2 impregnation, respectively, on PLA properties. Both strategies of incorporation of this active compound into PLA matrix resulted in different morphologies that influenced chemical and physical properties of these composites and in different release kinetics of CIN. The electrospinning and scCO2 impregnation processes and the presence of CIN altered PLA thermal and structural properties when compared to an extruded PLA material. The incorporation of CIN through scCO2 impregnation resulted in higher release rate and lower diffusion coefficients when compared to active electrospun mats with CIN incorporated during the electrospinning process.

  7. [Left versus bi-atrial radiofrequency ablation in the treatment of atrial fibrillation].

    Science.gov (United States)

    Wang, Jian-Gang; Meng, Xu; Li, Hui

    2008-11-25

    To evaluate the effectiveness of radiofrequency modified maze operation for the treatment of atrial fibrillation (AF) and compare the results of the left versus bi-atrial procedures. 305 patients of organic heart disease combined with AF, 117 males and 188 females, aged (53 +/- 10), that underwent cardiac valve operation (n = 293) and/or coronary artery bypass graft surgery (n = 14), received concomitant atrial fibrillation, bi-atrial (n = 160) or left atrial (n = 145) with a mean duration of (36 +/- 43) months. Follow-up was conducted for (28 +/- 5) (3 - 42) months. Thirteen patients (4.3%) died postoperatively: 7 died of multisystem and organ failure, 3 of low cardiac output, 1 of rupture of left ventricle, 1 of arrhythmia, and 1 of sudden death. During the follow-up, 1 patient died of heart failure, 1 of encephalorrhagia and 1 of unknown reason in the bi-atrial group. At the end of the procedure 223 patients (73.1%) had sinus rhythm, with a sinus rhythm rate of 66.9% (107/160) in the bi-atrial group, significant lower than that in the left atrial group (80.0%, 116/145, P bi-atrial group was 80.0%, not significantly different from that of the left atrial group (81.9%, P > 0.05). The Kaplan-Meier survival analysis showed there was no significant difference in the AF rhythm rate between these 2 groups (P = 0.33). Logistic regression analysis showed that the left atrial diameter of >/= 80 mm was an independent predictor of AF recurrence. Both the left and bi-atrial procedures are successful in terms of restoring sinus rhythm. Left atrial ablation in severe cases and where the incision of right atrium is not needed is a reasonable choice.

  8. Mitochondria-localized phospholipase A2, AoPlaA, in Aspergillus oryzae displays phosphatidylethanolamine-specific activity and is involved in the maintenance of mitochondrial phospholipid composition.

    Science.gov (United States)

    Kotani, Shohei; Izawa, Sho; Komai, Noriyuki; Takayanagi, Ayumi; Arioka, Manabu

    2016-11-01

    In mammals, cytosolic phospholipases A 2 (cPLA 2 s) play important physiological roles by releasing arachidonic acid, a precursor for bioactive lipid mediators, from the biological membranes. In contrast, fungal cPLA 2 -like proteins are much less characterized and their roles have remained elusive. AoPlaA is a cPLA 2 -like protein in the filamentous fungus Aspergillus oryzae which, unlike mammalian cPLA 2 , localizes to mitochondria. In this study, we investigated the biochemical and physiological functions of AoPlaA. Recombinant AoPlaA produced in E. coli displayed Ca 2+ -independent lipolytic activity. Mass spectrometry analysis demonstrated that AoPlaA displayed PLA 2 activity to phosphatidylethanolamine (PE), but not to other phospholipids, and generated 1-acylated lysoPE. Catalytic site mutants of AoPlaA displayed almost no or largely reduced activity to PE. Consistent with PE-specific activity of AoPlaA, AoplaA-overexpressing strain showed decreased PE content in the mitochondrial fraction. In contrast, AoplaA-disruption strain displayed increased content of cardiolipin. AoplaA-overexpressing strain, but not its counterparts overexpressing the catalytic site mutants, exhibited retarded growth at low temperature, possibly because of the impairment of the mitochondrial function caused by excess degradation of PE. These results suggest that AoPlaA is a novel PE-specific PLA 2 that plays a regulatory role in the maintenance of mitochondrial phospholipid composition. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Left Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    Khuansiri Narajeenron

    2017-04-01

    Full Text Available Audience: The audience for this classic team-based learning (cTBL session is emergency medicine residents, faculty, and students; although this topic is applicable to internal medicine and family medicine residents. Introduction: A left ventricular assist device (LVAD is a mechanical circulatory support device that can be placed in critically-ill patients who have poor left ventricular function. After LVAD implantation, patients have improved quality of life.1 The number of LVAD patients worldwide continues to rise. Left-ventricular assist device patients may present to the emergency department (ED with severe, life-threatening conditions. It is essential that emergency physicians have a good understanding of LVADs and their complications. Objectives: Upon completion of this cTBL module, the learner will be able to: 1 Properly assess LVAD patients’ circulatory status; 2 appropriately resuscitate LVAD patients; 3 identify common LVAD complications; 4 evaluate and appropriately manage patients with LVAD malfunctions. Method: The method for this didactic session is cTBL.

  10. Development and Characterization of Cefoxitin Loaded D,L-PLA Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sílvia Regina Pengo Machado

    2010-12-01

    Full Text Available Nanoparticles containing cefoxitin (CEF made of D,L-PLA (PLA were designed by a multiple emulsion/solvent evaporation method. The particles were extensively evaluated in relation to morphology, encapsulation efficiency, drug-polymer interactions as well as in vitro drug release kinetics. Nanoparticles were spherical in shape and isolated, with a mean diameter of about 600 nm. The thermal behaviour (DSC of CEF-containing nanoparticles suggested that the drug was dispersed at a molecular level within the system. The drug encapsulation efficiency in the system for a CEF concentration of 30 mg/mL was 5.5%, as assessed after the drug extraction, by a validated HPLC method. This low encapsulation efficiency is understandable, since CEF is highly hydrophilic. The in vitro assays showed a strong sustained drug release profile from the nanoparticles with kinetics following pure Fickian diffusion. Keywords: Nanoparticles. Controlled release. D,L-PLA. Cefoxitin. In vitro release. RESUMO Desenvolvimento e Caracterização de Nanopartículas de D,L-PLA contendo Cefoxitina As nanopartículas de D, L-PLA (PLA contendo cefoxitina (CEF foram preparadas pelo método de emulsão múltipla / evaporação do solvente. As partículas foram avaliadas em relação à morfologia, à eficiência de encapsulação, às interações polímero-fármaco, bem como à cinética de liberação do fármaco in vitro . As nanopartículas são esféricas e isoladas, com um diâmetro médio de cerca de 600 nm. O comportamento térmico (DSC das nanopartículas contendo CEF sugeriu que o fármaco está disperso em um nível molecular dentro do sistema. A eficiência de encapsulação do fármaco no sistema quando a concentração de CEF é 30 mg / mL foi de 5,5%, determinada após a extração de fármaco, através de um método de HPLC validado. Esta baixa eficiência de encapsulação é compreensível, uma vez que a CEF é altamente hidrofílica. Os ensaios in vitro mostraram um

  11. Investigation of Ultrasonics as a tool for energy efficient recycling of Lactic acid from postconsumer PLA products

    Science.gov (United States)

    Srinivasan, Gowrishankar

    The growing use of "ecofriendly," biodegradable polymers have created a need for a suitable recycling technique because, unlike petroleum derived plastics, their properties deteriorate during conventional recycling. These new techniques must be cost efficient and yield material properties same as virgin polymer. This research investigates the effectiveness of high-power ultrasonics as an efficient technique to recover lactic acid from postconsumer polylactic acid (PLA) products. Polylactic acid is a commercially available bioplastic derived from corn starch and/or sugar cane that is biorenewable and compostable (biodegradable). The various ongoing researches to recover lactic acid from PLA employ a common platform of high temperature, high pressure (HTHP) to effect polymer hydrolysis. The energy intensiveness of these HTHP processes prompted this work to investigate ultrasonics as an low energy alternative process to cause PLA depolymerization. The energy consumption and the time required for depolymerization were utilized as the metrics to quantify and compare depolymerization enhanced by ultrasonics with hot-bath technique. The coupled effect of catalysts concentration and different solvents, along with ultrasonic were studied based on preliminary trial results. In addition, the correlation between the rates of de-polymerization was analyzed for ultrasonic amplitude, treatment time, and catalyst concentration and types. The results indicate that depolymerization of PLA was largely effected by heating caused by ultrasonic-induced cavitations. Other effects of ultrasonics, namely cavitations and acoustic streaming, were shown to have minimal effects in enhancing depolymerization. In fact, thermal energy predominately affected the reaction kinetics; the heat introduced by conventional method (i.e., electrical heaters) was more efficient than ultrasonic heating in terms of energy (for depolymerization) per unit mass of PLA and depolymerizing time. The degree of

  12. Infective Endocarditis of the Left Main to Right Atrial Coronary Cameral Fistula

    Science.gov (United States)

    Mishra, Ramesh Chandra; Barik, Ramachandra; Patnaik, Amar Narayana

    2016-01-01

    A 7-year-old female child presented with pyrexia of unknown origin. She had received an empirical regimen of antibiotic for possible endocarditis. Evaluation included multiple imaging supports and blood culture. She had left main coronary artery to right atrium coronary cameral fistula, restricted patent ductus arteriosus, vegetation at the right atrial exit of fistula and negative blood culture. Ongoing fever more than 2 weeks, oscillating vegetation in the echo and histopathological evidence of healing vegetation suggested definite diagnosis of infective endocarditis. She was treated successfully by surgical closure of fistula from the right atrial approach. Device closure in this case would have resulted in a large residual cul-de-sac with or without tiny residual high-velocity jets, either being a threat for future enlargement, rupture of the residual aneurysmal sac, thromboembolism, prolonged anticoagulation, and infective endocarditis. PMID:28465978

  13. Fully automated left ventricular contour detection for gated radionuclide angiography, (1)

    International Nuclear Information System (INIS)

    Hosoba, Minoru; Wani, Hidenobu; Hiroe, Michiaki; Kusakabe, Kiyoko.

    1984-01-01

    A fully automated practical method has been developed to detect the left ventricular (LV) contour from gated pool images. Ejection fraction and volume curve can be computed accurately without operater variance. The characteristics of the method are summarized as follows: 1. Optimal design of the filter that works on Fourier domain, can be achieved to improve the signal to noise ratio. 2. New algorithm which use the cosine and sine transform images has been developed for the separating ventricle from atrium and defining center of LV. 3. Contrast enhancement by optimized square filter. 4. Radial profiles are generated from the center of LV and smoothed by fourth order Fourier series approximation. The crossing point with local threshold value searched from the center of the LV is defined as edge. 5. LV contour is obtained by conecting all the edge points defined on radial profiles by fitting them to Fourier function. (author)

  14. An Unusual Left Ventricular Outflow Pseudoaneurysm: Usefulness of Echocardiography and Multidetector Computed Tomography for Surgical Repair

    International Nuclear Information System (INIS)

    Da Col, Uberto; Ramoni, Enrico; Di Bella, Isidoro; Ragni, Temistocle

    2009-01-01

    Left ventricular outflow tract (LVOT) pseudoaneurysm is a rare but potentially lethal complication, mainly after aortic root endocarditis or surgery. Usually it originates from a dehiscence in the mitral-aortic intervalvular fibrosa and it arises posteriorly to the aortic root. Due to these anatomical features, its imaging assessment is challenging and surgical repair requires complex procedures. An unusual case of LVOT pseudoaneurysm is described. It was detected by transthoracic ecocardiography 7 months after aortic root replacement for acute endocarditis. Multidetector computed tomography (MDCT) confirmed the presence of a pouch located between the aortic root and the right atrium. Computed tomography also detected the origin of the pseudoaneurysm from the muscular interventricular septum of the LVOT, rather below the aortic valve plane. It was repaired with an extracardiac surgical approach, sparing the aortic root bioprosthesis previously implanted. The high-resolution three-dimensional details provided by the preoperative MDCT allowed us to plan a simple and effective surgical strategy.

  15. Hydrolysis of lipoproteins by sPLA2's enhances mitogenesis and eicosanoid release from vascular smooth muscle cells: Diverse activity of sPLA2's IIA, V and X.

    Science.gov (United States)

    Pruzanski, Waldemar; Kopilov, Julia; Kuksis, Arnis

    2016-01-01

    Mitogenesis of Vascular Smooth Muscle Cells (VSMC) plays an important role in atherogenesis. Until recently, the effect of lipid subfractions has not been clarified. Secretory phospholipases A2 (sPLA2's) hydrolyse glycerophospholipids and release pro-inflammatory lyso-lipids, oxidized and non-oxidized fatty acids and isoprostanes. They localize in the vascular wall. We hypothesized that structurally similar sPLA2's may exert different impact on VSMC. The influence of sPLA2's, IIA, V, X, HDL, LDL, and hydrolysis products was tested on mitogenesis of VSMC, i.e., the early effect on the cell membrane phospholipids, and on PGE2 and LTB4 release, i.e., late effect of Cyclooxygenase and 5-lipooxygenase activity in VSMC. Mitogenesis was significantly enhanced by HDL and LDL, and by products of sPLA2 hydrolysis. Hydrolysis of HDL or LDL enhanced mitogenic activity in order V>X>IIA. The release of PGE2 was enhanced by group X sPLA2 and by HDL hydrolyzed by groups V and X. LDL and its hydrolysis products enhanced the release of PGE2 in order X>V>IIA. The release of LTB4 was markedly increased by LDL and HDL, and by hydrolytic products of group V and X, but not group IIA sPLA2. Our study demonstrates a diverse interaction of pro-inflammatory sPLA2's with HDL and LDL affecting both mitogenesis and eicosanoid release from VSMC, therefore potentially enhancing their pro-atherogenic activity. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Prevention of Cerebral Embolism Progression by Emergency Surgery of the Left Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Syuichi Tetsuka

    2015-01-01

    Full Text Available A 21-year-old woman developed left hemiparesis during work and was hospitalized. Her National Institutes of Health Stroke Scale score was 4. Hyperintense areas in the left basal ganglia, corona radiata, and cortex of the temporal lobe were found by brain diffusion-weighted magnetic resonance imaging, indicating acute cerebral infarction. Echocardiography showed a giant mass of diameter 7 × 4 cm in the left atrium. Therefore, she was diagnosed with cerebral embolism due to a left atrial myxoma. Currently, thrombolytic therapy may continue to be effective because the embolic source may be composed of tumor tissue itself. In case of atrial myxoma, we considered that the use of tPA as emergency treatment in all patients with infarction by atrial myxoma may be questioned. Thus, cardiac tumor extraction was performed the next day after hospitalization without thrombolytic therapy. The excised myxoma measured 7 × 6 × 4 cm. The patient recovered and her neurological symptoms also improved. Furthermore, her National Institutes of Health Stroke Scale score improved to 0. Thirteen days after admission, the patient was discharged from our hospital. Cardiac myxoma is often associated with a high risk of embolic episodes, which emphasizes the need for prompt surgical excision as soon as the diagnosis is confirmed.

  17. Long-term survival of quiescent left atrial myxoma in an elderly patient.

    Science.gov (United States)

    Kay, Jay F L; Chow, Wing Hing

    2002-01-01

    Left atrial myxoma, if left untreated, is inexorably progressive and usually fatal. The classical management of this disease is prompt surgical removal. However, there may be exceptions to this traditional dogma. The authors report an 85-year-old man who presented with features of chronic obstructive airway disease and congestive heart failure 15 years previously. Auscultation of the heart showed a pansystolic murmur. Two-dimensional echocardiography revealed a nonobstructive, calcified, and well circumscribed mass in the left atrium, with a pedicle attached to the interatrial septum. Because the patient refused high-risk cardiac surgery related to his comorbidity, he was managed medically with a bronchodilator, diuretics, and digoxin. There have been no features of embolism or intracardiac obstruction, and serial echocardiography demonstrates no disease progression over this long period of time. This case illustrates that calcified left atrial myxoma may exhibit a quiescent phase. Tumor calcification, slow growth potential, and the absence of intracardiac obstruction may correlate with a better outcome in the elderly patient. (c)2002 CVRR, Inc.

  18. Predictors of transient left ventricular dysfunction following transcatheter patent ductus arteriosus closure in pediatric age.

    Science.gov (United States)

    Agha, Hala Mounir; Hamza, Hala S; Kotby, Alyaa; Ganzoury, Mona E L; Soliman, Nanies

    2017-10-01

    To evaluate the left ventricular function before and after transcatheter percutaneous patent ductus arteriosus (PDA) closure, and to identify the predictors of myocardial dysfunction post-PDA closure if present. Transcatheter PDA closure; conventional, Doppler, and tissue Doppler imaging; and speckle tracking echocardiography. To determine the feasibility and reliability of tissue Doppler and myocardial deformation imaging for evaluating myocardial function in children undergoing transcatheter PDA closure. Forty-two children diagnosed with hemodynamically significant PDA underwent percutaneous PDA closure. Conventional, Doppler, and tissue Doppler imaging, and speckle-derived strain rate echocardiography were performed at preclosure and at 48 hours, 1 month, and 6 months postclosure. Tissue Doppler velocities of the lateral and septal mitral valve annuli were obtained. Global and regional longitudinal peak systolic strain values were determined using two-dimensional speckle tracking echocardiography. The median age of the patients was 2 years and body weight was 15 kg, with the mean PDA diameter of 3.11 ± 0.99 mm. M-mode measurements (left ventricular end diastolic diameter, left atrium diameter to aortic annulus ratio, ejection fraction, and shortening fraction) reduced significantly early after PDA closure ( p  closure causes a significant decrease in left ventricular performance early after PDA closure, which recovers completely within 1 month. Preclosure global longitudinal strain can be a predictor of postclosure myocardial dysfunction.

  19. Assessment of blood stasis in left-atrial appendage with electron-beam CT: filling delay in atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Tadashi [Dept. of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Hamada, Seiki [Dept. of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Takamiya, Makoto [Dept. of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Kuribayashi, Sachio [Dept. of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Naito, Hiroaki [Biomedical Research Center, Osaka Univ. School of Medicine, Suita (Japan)

    1994-10-01

    The left-atrial appendage (LAA) is the most frequent site of thrombus formation. The most probable reason is its anatomical structure and blood stasis. We hypothesized that peak time delay should occur in the LAA with stagnant blood flow. We measured peak time delay in LAA against left atrium with the flow-mode study of electron-beam CT for 49 patients (including 23 patients with atrial fibrillation [AF]). Volume-mode scannings were also performed to detect intracardiac thrombi. Patients with atrial fibrillation showed a larger value than those with sinus rhythm. Some AF patients with no filling of contrast media into the LAA and/or thrombus showed a larger value than the others. The value obtained by the flow-mode study might have the potential by the flow-mode study might have the potential to assess blood stasis and to predict the jeopardized state in the LAA. (orig.)

  20. Assessment of blood stasis in left-atrial appendage with electron-beam CT: filling delay in atrial fibrillation

    International Nuclear Information System (INIS)

    Nakanishi, Tadashi; Hamada, Seiki; Takamiya, Makoto; Kuribayashi, Sachio; Naito, Hiroaki

    1994-01-01

    The left-atrial appendage (LAA) is the most frequent site of thrombus formation. The most probable reason is its anatomical structure and blood stasis. We hypothesized that peak time delay should occur in the LAA with stagnant blood flow. We measured peak time delay in LAA against left atrium with the flow-mode study of electron-beam CT for 49 patients (including 23 patients with atrial fibrillation [AF]). Volume-mode scannings were also performed to detect intracardiac thrombi. Patients with atrial fibrillation showed a larger value than those with sinus rhythm. Some AF patients with no filling of contrast media into the LAA and/or thrombus showed a larger value than the others. The value obtained by the flow-mode study might have the potential by the flow-mode study might have the potential to assess blood stasis and to predict the jeopardized state in the LAA. (orig.)