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Sample records for reversed double pcl

  1. Reversed double PCL sign: unusual location of a meniscal fragment of the knee observed by MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Niitsu, M.; Itai, Y. [Dept. of Radiology, Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan); Ikeda, K. [Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan)

    2003-12-01

    A 36-year-old woman with tears of the anterior cruciate ligament and medial meniscus received a meniscectomy. The MR images obtained prior to the partial meniscectomy showed a bucket-handle meniscal tear with centrally displaced fragment lying anterior to the posterior cruciate ligament (PCL), representing a ''double PCL sign''; however, after the meniscectomy, MR images demonstrated a fragment in the space posterior to the PCL where no structure is generally recognized except for the ligament of wrisberg. This article reports a ''reversed'' double PCL sign, caused by inadequate surgical clearance of a bucket-handle tear of the medial meniscus. (orig.)

  2. ACL-PCL and intercondylar notch impingement: magnetic resonance imaging of native and double-bundle ACL-reconstructed knees.

    Science.gov (United States)

    Kropf, Eric J; Shen, Wei; van Eck, Carola F; Musahl, Volker; Irrgang, James J; Fu, Freddie H

    2013-03-01

    The purpose of this study was to: (1) define the relationship between the ACL and PCL in normal knees; (2) determine whether ACL-PCL impingement occurs in native knees; and (3) determine whether there is a difference in impingement between double-bundle reconstructed and native knees. Eight subjects were identified (age 20-50; 6 females, 2 males). All were at least 1-year status postanatomic double-bundle ACL reconstruction (allograft; AM = 8 mm; PL = 7 mm) and had no history of injury or surgery to the contralateral knee. MRIs of both knees were performed with the knee at 0 and 30° of flexion. The images were evaluated by a non-treating surgeon and two musculoskeletal radiologists. Coronal and sagittal angles of AM and PL bundles, Liu's PCL index and the distance between ACL and PCL on modified axial oblique images were recorded. Impingement was graded (1) no contact; (2) contact without deformation; or (3) contact and distortion of PCL contour. Seventy-five percent (6) of the native ACL's showed no contact with the roof of the intercondylar notch or PCL, compared to 25 % (2) of the double-bundle reconstructed ACLs. One double-bundle reconstructed ACL showed intercondylar notch roof and ACL-PCL impingement (12.5 %). Significant differences were found between the native ACL and the double-bundle reconstructed ACL for the coronal angle of the AM (79° vs. 72°, p = 0.002) and PL bundle (75° vs. 58°, p = 0.001). No differences in ROM or stability were noted at any follow-up interval between groups based on MRI impingement grade. ACL-PCL contact occurred in 25 % of native knees. Contact between the ACL graft and PCL occurred in 75 % of double-bundle reconstructed knees. ACL-PCL impingement, both contact and distortion of the PCL, occurred in one knee after double-bundle reconstruction. This study offers perspective on what can be considered normal contact between the ACL and PCL and how impingement after ACL reconstruction can be detected on MRI

  3. Evaluation of Single-Bundle versus Double-Bundle PCL Reconstructions with More Than 10-Year Follow-Up

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    Masataka Deie

    2015-01-01

    Full Text Available Background. Posterior cruciate ligament (PCL injuries are not rare in acute knee injuries, and several recent anatomical studies of the PCL and reconstructive surgical techniques have generated improved patient results. Now, we have evaluated PCL reconstructions performed by either the single-bundle or double-bundle technique in a patient group followed up retrospectively for more than 10 years. Methods. PCL reconstructions were conducted using the single-bundle (27 cases or double-bundle (13 cases method from 1999 to 2002. The mean age at surgery was 34 years in the single-bundle group and 32 years in the double-bundle group. The mean follow-up period was 12.5 years. Patients were evaluated by Lysholm scoring, the gravity sag view, and knee arthrometry. Results. The Lysholm score after surgery was 89.1±5.6 points for the single-bundle group and 91.9±4.5 points for the double-bundle group. There was no significant difference between the methods in the side-to-side differences by gravity sag view or knee arthrometer evaluation, although several cases in both groups showed a side-to-side difference exceeding 5 mm by the latter evaluation method. Conclusions. We found no significant difference between single- and double-bundle PCL reconstructions during more than 10 years of follow-up.

  4. Coexistence of Reverse Capgras Syndrome, Subjective Double and Cotard Syndrome

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    Azadeh Mashayekhi

    2016-01-01

    Full Text Available Misidentification syndrome is a condition in which the person thinks that familiar persons have been replaced with other one. Coexistence of some types of this syndrome has been reported with other psychiatric syndromes. In this report, we present a 47-year-old married man with coexistence of reverse Capgras and subjective double syndromes with Cotard syndrome. There is no previous report of coexistence of these three forms of delusions in a single case.

  5. Supramolecular self-assembly of novel thermo-responsive double-hydrophilic and hydrophobic Y-shaped [MPEO-b-PEtOx-b-(PCL)2] terpolymers

    Czech Academy of Sciences Publication Activity Database

    Petrova, Svetlana; Venturini, Cristina Garcia; Jäger, Alessandro; Jäger, Eliezer; Hrubý, Martin; Pavlova, Ewa; Štěpánek, Petr

    2015-01-01

    Roč. 5, č. 77 (2015), s. 62844-62854 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) LH14079; GA MŠk(CZ) 7F14009 Institutional support: RVO:61389013 Keywords : Y-shaped [PEO-b-PEtOx-b-(PCL)2] terpolymers * light scattering * nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.289, year: 2015

  6. Critical Perspectives of Pedagogical Approaches to Reversing the Order of Integration in Double Integrals

    Science.gov (United States)

    Tisdell, Christopher C.

    2017-01-01

    This paper presents some critical perspectives regarding pedagogical approaches to the method of reversing the order of integration in double integrals from prevailing educational literature on multivariable calculus. First, we question the message found in popular textbooks that the traditional process of reversing the order of integration is…

  7. The effect of a dynamic PCL brace on patellofemoral compartment pressures in PCL-and PCL/PLC-deficient knees.

    Science.gov (United States)

    Welch, Tyler; Keller, Thomas; Maldonado, Ruben; Metzger, Melodie; Mohr, Karen; Kvitne, Ronald

    2017-12-01

    The natural history of posterior cruciate ligament (PCL) deficiency includes the development of arthrosis in the patellofemoral joint (PFJ). The purpose of this biomechanical study was to evaluate the hypothesis that dynamic bracing reduces PFJ pressures in PCL- and combined PCL/posterolateral corner (PLC)-deficient knees. Controlled Laboratory Study. Eight fresh frozen cadaveric knees with intact cruciate and collateral ligaments were included. PFJ pressures and force were measured using a pressure mapping system via a lateral arthrotomy at knee flexion angles of 30°, 60°, 90°, and 120° in intact, PCL-deficient, and PCL/PLC-deficient knees under a combined quadriceps/hamstrings load of 400 N/200 N. Testing was then repeated in PCL- and PCL/PLC-deficient knees after application of a dynamic PCL brace. Application of a dynamic PCL brace led to a reduction in peak PFJ pressures in PCL-deficient knees. In addition, the brace led to a significant reduction in peak pressures in PCL/PLC-deficient knees at 60°, 90°, and 120° of flexion. Application of the dynamic brace also led to a reduction in total PFJ force across all flexion angles for both PCL- and PCL/PLC-deficient knees. Dynamic bracing reduces PFJ pressures in PCL- and combined PCL/PLC-deficient knees, particularly at high degrees of knee flexion.

  8. Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

    Science.gov (United States)

    Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

    2013-02-01

    Oral chemotherapy is a key step towards `chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

  9. PCL and PCL-based materials in biomedical applications.

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    Malikmammadov, Elbay; Tanir, Tugba Endogan; Kiziltay, Aysel; Hasirci, Vasif; Hasirci, Nesrin

    2017-11-02

    Biodegradable polymers have met with an increasing demand in medical usage over the last decades. One of such polymers is poly(ε-caprolactone) (PCL), which is a polyester that has been widely used in tissue engineering field for its availability, relatively inexpensive price and suitability for modification. Its chemical and biological properties, physicochemical state, degradability and mechanical strength can be adjusted, and therefore, it can be used under harsh mechanical, physical and chemical conditions without significant loss of its properties. Degradation time of PCL is quite long, thus it is used mainly in the replacement of hard tissues in the body where healing also takes an extended period of time. It is also used at load-bearing tissues of the body by enhancing its stiffness. However, due to its tailorability, use of PCL is not restricted to one type of tissue and it can be extended to engineering of soft tissues by decreasing its molecular weight and degradation time. This review outlines the basic properties of PCL, its composites, blends and copolymers. We report on various techniques for the production of different forms, and provide examples of medical applications such as tissue engineering and drug delivery systems covering the studies performed in the last decades.

  10. A historical perspective of PCL bracing.

    Science.gov (United States)

    Jansson, Kyle S; Costello, Kerry E; O'Brien, Luke; Wijdicks, Coen A; Laprade, Robert F

    2013-05-01

    Currently there are many functional knee braces but very few designed to treat the posterior cruciate ligament (PCL). No PCL braces have been biomechanically validated to demonstrate that they provide stability with proper force distribution to the PCL-deficient knee. The purpose of this review was to evaluate the history and current state of PCL bracing and to identify areas where further progress is required to improve patient outcomes and treatment options. A PubMed search was conducted with the terms "posterior cruciate ligament", "rehabilitation", "history", "knee", and "brace", and the relevant articles from 1967 to 2011 were analysed. A review of the current available PCL knee bracing options was performed. Little evidence exists from the eight relevant articles to support the biomechanical efficacy of nonoperative and postoperative PCL bracing protocols. Clinical outcomes reported improvements in reducing PCL laxity with anterior directed forces to the tibia during healing following PCL tears. Biomechanics research demonstrates that during knee flexion, the PCL experiences variable tensile forces. One knee brace has been specifically designed and clinically validated to improve stability in PCL-deficient knees during rehabilitation. While available PCL braces demonstrate beneficial patient outcomes, they lack evidence validating their biomechanical effectiveness. There is limited information evaluating the specific effectiveness of PCL knee braces. A properly designed PCL brace should apply correct anatomic joint forces that vary with the knee flexion angle and also provide adjustability to satisfy the demands of various activities. No braces are currently available with biomechanical evidence that satisfies these requirements. IV.

  11. Flux amplification of a field-reversed configuration by double-sided plasmoid injection

    Science.gov (United States)

    Itagaki, H.; Asai, T.; Inomoto, M.; Takahashi, Ts.

    2017-08-01

    Trapped magnetic flux in a field-reversed configuration (FRC) plasma was amplified by double-sided magnetized plasmoid injection. Since the magnetic energy in plasmoids was much less than that in the FRC, the FRC's magnetic flux was presumed to be enhanced by the increased diamagnetic current. The plasmoids supplied particles to the FRC from the both ends and increased the peak pressure as well as the pressure gradient in the vicinity of the separatrix.

  12. Double-temperature ratchet model and current reversal of coupled Brownian motors

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    Li, Chen-Pu; Chen, Hong-Bin; Zheng, Zhi-Gang

    2017-12-01

    On the basis of the transport features and experimental phenomena observed in studies of molecular motors, we propose a double-temperature ratchet model of coupled motors to reveal the dynamical mechanism of cooperative transport of motors with two heads, where the interactions and asynchrony between two motor heads are taken into account. We investigate the collective unidirectional transport of coupled system and find that the direction of motion can be reversed under certain conditions. Reverse motion can be achieved by modulating the coupling strength, coupling free length, and asymmetric coefficient of the periodic potential, which is understood in terms of the effective potential theory. The dependence of the directed current on various parameters is studied systematically. Directed transport of coupled Brownian motors can be manipulated and optimized by adjusting the pulsation period or the phase shift of the pulsation temperature.

  13. Ultrafast optical reversible double Feynman logic gate using electro-optic effect in lithium-niobate based Mach Zehnder interferometers

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    Chauhan, Chanderkanta; Bedi, Amna; Kumar, Santosh

    2017-02-01

    In this ultra fast computing era power optimization is a major technological challenge that requires new computing paradigms. Conservative and reversible logic opens up the possibility of ultralow power computing. In this paper, basic reversible logic gate (double Feynman gate) using the lithium-niobate based Mach-Zehnder interferometer is proposed. The results are verified using beam propagation method and MATLAB simulations.

  14. Imaging of posterior cruciate ligament (PCL) reconstruction: normal postsurgical appearance and complications

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    Alcala-Galiano, Andrea; Baeva, Maria; Jose Argueeso, Maria [Hospital ASEPEYO Coslada, Department of Radiology, Madrid (Spain); Ismael, Maryem [Hospital ASEPEYO Coslada, Department of Traumatology and Orthopaedic Surgery, Madrid (Spain)

    2014-12-15

    This article reviews the normal postsurgical anatomy and appearance of PCL reconstructions on MDCT and MRI with the different operative techniques considering the type of tibial fixation, use of a single or double bundle, type of tendon graft and the fixation material. Tunnel positioning, appearance of the ligament graft and findings at the donor site are considered. Imaging signs of PCL graft failure and its possible causes are discussed. Imaging manifestations of other potential complications of both the PCL graft and donor sites are described, such as laxity, impingement, arthrofibrosis, ganglion cyst formation or complications related to the fixation material. (orig.)

  15. Posterior cruciate ligament (PCL) injury -- aftercare

    Science.gov (United States)

    ... you are younger, having a torn PCL and instability of your knee may lead to arthritis as ... Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, ...

  16. Properties Of Pla/pcl Particles As Vehicles For Oral Delivery Of The Androgen Hormone 17α-methyltestosterone.

    OpenAIRE

    Sacchetin, Priscila Soares Costa; Setti, Rafaela Ferreira; Vieira e Rosa, Paulo de Tarso; Moraes,Ângela Maria

    2016-01-01

    The aim of this study was to produce PLA (poly(lactic acid)) and PCL (polycaprolactone) oral carriers through the precipitation of the polymer solutions using supercritical CO2 as an antisolvent for the controlled release of the hydrophobic model drug 17α-methyltestosterone (MT). Such drug is a steroidal hormone used orally to develop and sustain primary and secondary male sex characteristics, e.g. for female Nile tilapia sex reversal in aquaculture. The influence of hormone, PLA and PCL conc...

  17. Precision Extruding Deposition for Freeform Fabrication of PCL and PCL-HA Tissue Scaffolds

    Science.gov (United States)

    Shor, L.; Yildirim, E. D.; Güçeri, S.; Sun, W.

    Computer-aided tissue engineering approach was used to develop a novel Precision Extrusion Deposition (PED) process to directly fabricate Polycaprolactone (PCL) and composite PCL/Hydroxyapatite (PCL-HA) tissue scaffolds. The process optimization was carried out to fabricate both PCL and PCL-HA (25% concentration by weight of HA) with a controlled pore size and internal pore structure of the 0°/90° pattern. Two groups of scaffolds having 60 and 70% porosity and with pore sizes of 450 and 750 microns, respectively, were evaluated for their morphology and compressive properties using Scanning Electron Microscopy (SEM) and mechanical testing. The surface modification with plasma was conducted on PCL scaffold to increase the cellular attachment and proliferation. Our results suggested that inclusion of HA significantly increased the compressive modulus from 59 to 84 MPa for 60% porous scaffolds and from 30 to 76 MPa for 70% porous scaffolds. In vitro cell-scaffolds interaction study was carried out using primary fetal bovine osteoblasts to assess the feasibility of scaffolds for bone tissue engineering application. In addition, the results in surface hydrophilicity and roughness show that plasma surface modification can increase the hydrophilicity while introducing the nano-scale surface roughness on PCL surface. The cell proliferation and differentiation were calculated by Alamar Blue assay and by determining alkaline phosphatase activity. The osteoblasts were able to migrate and proliferate over the cultured time for both PCL as well as PCL-HA scaffolds. Our study demonstrated the viability of the PED process to the fabricate PCL and PCL-HA composite scaffolds having necessary mechanical property, structural integrity, controlled pore size and pore interconnectivity desired for bone tissue engineering.

  18. Smoking cessation reverses DNA double-strand breaks in human mononuclear cells.

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    Mari Ishida

    Full Text Available OBJECTIVE: Cigarette smoking is a major risk factor for atherosclerotic cardiovascular disease, which is responsible for a significant proportion of smoking-related deaths. However, the precise mechanism whereby smoking induces this pathology has not been fully delineated. Based on observation of DNA double-strand breaks (DSBs, the most harmful type of DNA damage, in atherosclerotic lesions, we hypothesized that there is a direct association between smoking and DSBs. The goal of this study was to investigate whether smoking induces DSBs and smoking cessation reverses DSBs in vivo through examination of peripheral mononuclear cells (MNCs. APPROACH AND RESULTS: Immunoreactivity of oxidative modification of DNA and DSBs were increased in human atherosclerotic lesions but not in the adjacent normal area. DSBs in human MNCs isolated from the blood of volunteers can be detected as cytologically visible "foci" using an antibody against the phosphorylated form of the histone H2AX (γ-H2AX. Young healthy active smokers (n = 15 showed increased γ-H2AX foci number when compared with non-smokers (n = 12 (foci number/cell: median, 0.37/cell; interquartile range [IQR], 0.31-0.58 vs. 4.36/cell; IQR, 3.09-7.39, p<0.0001. Smoking cessation for 1 month reduced the γ-H2AX foci number (median, 4.44/cell; IQR, 4.36-5.24 to 0.28/cell; IQR, 0.12-0.53, p<0.05. A positive correlation was noted between γ-H2AX foci number and exhaled carbon monoxide levels (r = 0.75, p<0.01. CONCLUSIONS: Smoking induces DSBs in human MNCs in vivo, and importantly, smoking cessation for 1 month resulted in a decrease in DSBs to a level comparable to that seen in non-smokers. These data reinforce the notion that the cigarette smoking induces DSBs and highlight the importance of smoking cessation.

  19. Hydrolytic and thermal degradation of PCL and PCL/Bentonite compounds

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    Franca, Danyelle Campos; Bezerra, Elieber Barros; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Engenharia de Materiais

    2016-05-15

    Poly(ε-caprolactone)/montmorillonite (PCL/MMT) and Poly(εcaprolactone)/organo-modified montmorillonite (PCL/OMMT) compounds at 3% w/w clay content were prepared by melting mixing. The effect of MMT and OMMT on the degradability of PCL injected specimens was investigated in vacuum at 40 deg C for up to 45 days and in aqueous medium at 40 deg C for up to 45 days. Selected specimens were collected after 15, 30 and 45 days of exposure. Microstructural changes were monitored during the degradation experiment by means of melt flow rate (MFR), weight loss, X ray diffraction (XRD), mechanical properties, and scanning electron microscopy (SEM). PCL and its compounds revealed not to be prone to hydrolytic degradation with similar results for MFR of samples exposed in vacuum and water. Gain and loss of weight were observed during experiments, probably due to swelling mechanism taking place in two stages, with the amorphous phase being the first to be swelled followed by the crystalline one. By XRD a new peak corresponding to (002) plane was evident for PCL/OMMT. PCL proved to be resistant to degradation since experiments carried out in vacuum or in aqueous medium for up to 45 days were not enough to affect the mechanical integrity of PCL samples. (author)

  20. Reverse Segond fracture and associated knee injuries: A case report and review of 13 published cases

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    Ozkan Kose

    2016-10-01

    Full Text Available Reverse Segond fracture is originally described as an indirect radiographic clue for a specific injury complex of the knee joint that includes posterior cruciate ligament (PCL rupture and medial meniscal tear. Herein, we describe a case with reverse Segond fracture associated with PCL avulsion fracture instead of PCL rupture. According to current literature review, reverse Segond fracture is not only associated with PCL and medial meniscal injuries, but also frequently associated with anterior cruciate ligament (ACL and medial collateral ligament (MCL injuries. Furthermore, medial meniscus and PCL may remain intact.

  1. PCL/MWCNT Nanocomposites as Nanosensors

    Science.gov (United States)

    Grozdanov, Anita; Buzarovska, Alexandra; Avella, Maurizio; Errico, Maria E.; Gentile, Gennaro

    Due to the unique electronic, metallic and structural properties of carbon nanotubes (CNTs) as compared to other materials, researchers focused on utilizing these characteristics for engineering applications such as actuators, hydrogen storage materials, chemical sensors and nanoelectronic devices. Many papers have been published utilizing CNTs as the sensing material in pressure, flow, thermal, gas, optical, mass, strain, stress, chemical and biological sensors. Amongst many of their superior electro-mechanical properties, the piezoresistive effect in CNTs is attractive for designing strain sensors. When CNTs are subjected to a mechanical strain, a change in their chirality leads to modulation of the conductance. In this paper, a novel carbon nanotube/biopolymer nanocomposite was used to develop a piezoresistive strain nano bio-sensor. A biocompatible polymer matrix has been used to provide good interfacial bonding between the carbon nanotubes. Multi-walled carbon nanotubes (MWCNT, diameter d = 30-50 nm, purity >95%) have been used for the preparation of polycaprolactone (PCL)-based nanocomposites (PCL/MWCNT). The nanocomposites were prepared by mixing the MWCNTs and PCL in a tetrahydrofuran solution for 24 h. Characterization of the PCL/MWCNTs nanocomposite films was performed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM), as well as by mechanical and electrical measurements.

  2. Processing and properties of PCL/cotton linter compounds

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    Bezerra, Elieber Barros; Franca, Danyelle Campos; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Rosa, Morsyleide de Freitas; Morais, Joao Paulo Saraiva [Embrapa Tropical Agroindustia, Fortaleza, CE (Brazil); Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiaba (UFPB), Joao Pessoa, PB (Brazil)

    2017-03-15

    Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton nanolinter compounds. Adding cotton linter to PCL did not change its crystalline character as showed by XRD; however an increase in degree of crystallinity was observed by means of DSC. From mechanical tests in tension was observed an increase in ductility of PCL, and from mechanical tests in flexion an increase in elastic modulus upon addition of cotton linter, whereas impact strength presented lower values for PCL/cotton linter and PCL/cotton nanolinter compounds. SEM images showed that PCL presents plastic fracture and cotton linter has an interlacing fibril structure with high L/D ratio, which are in agreement with matrix/fibril morphology observed for PCL/cotton linter compounds. PCL/cotton linter compounds made in this work cost less than neat PCL matrix and presented improved properties making feasible its commercial use. (author)

  3. Nanosized CaP-silk fibroin-PCL-PEG-PCL/PCL based bilayer membranes for guided bone regeneration.

    Science.gov (United States)

    Türkkan, Sibel; Pazarçeviren, A Engin; Keskin, Dilek; Machin, Nesrin E; Duygulu, Özgür; Tezcaner, Ayşen

    2017-11-01

    Guided bone regeneration (GBR) concept has been developed to prevent the formation of non-functional scar tissue layer on defect site by undertaking barrier role. In this study, a new bilayer membrane which consisted of one layer of electrospun silk fibroin/PCL-PEG-PCL incorporating nanocalcium phosphate (SPCA) 1 and one layer of PCL membrane was developed for GBR. To improve the osteoconductivity of membranes, nanosized calcium phosphate particles synthesized by Flame Spray Pyrolysis method were incorporated into membranes at 10% (wt) (SPCA10) and 20% (wt) (SPCA20) of the polymer content. The structural and chemical analyses revealed the well-integrated two layers of membranes with a total thickness of ca 100μm. In the regenerative layer, the highly porous mesh structure had a thickness of 12.6μm with randomly oriented fibers having diameters around 760nm, and nanoparticles dispersed homogenously. The mechanical test results showed remarkable improvement on the tensile strength of membranes with incorporation of nanoparticles. Higher water affinity of nanoCaP included membranes was proved by lower contact angle values and higher percent water uptake capacity. Biomineralization assay revealed that nucleation and growth of apatites around fibers of SPCA10 and SPCA20 were apparent while on SPCA0 apatite minerals were barely detected after 10days. Human dental pulp stem cells (DPSC) were seeded on electrospun layer of the bilayer membranes for biocompatibility and osteo-compatibility study. Increasing nanoCaP amount resulted in higher cell adhesion, proliferation, ALP activity and calcium deposition on membranes. These overall results confirmed the biocompatibility and potential applicability of proposed membranes for GBR treatments. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Reversible Ionic Liquids as Double-Action Solvents for Efficient CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Charles Eckert; Charles Liotta

    2011-09-30

    We have developed a novel class of CO{sub 2} capture solvents, Reversible Ionic Liquids (RevILs), that offer high absorption capacity through two modes of capture: chemical reaction (chemisorption) and physical solubility (physisorption). These solvents are silicon containing alkaline compounds such as silylamines that form a liquid salt (ionic liquid) upon reaction with CO{sub 2}. Subsequently, modest elevations in temperature reverse the reaction and yield pure CO{sub 2} for sequestration. By incorporating Si in the molecules we have reduced the viscosity, thereby improving the mass transfer rates of CO{sub 2} absorption/desorption and decreasing the processing costs for pumping the solvent. In this project, we have made systematic changes to the structure of these compounds to improve several physical and thermodynamic properties important for CO{sub 2} capture. Through these structure-property paradigms, we have obtained a RevIL which requires only a third of the energy required by conventional aqueous MEA process for 90% CO{sub 2} capture.

  5. Reversible Ionic Liquids as Double-Action Solvents for Efficient CO2 Capture

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Charles; Liotta, Charles

    2011-09-30

    We have developed a novel class of CO{sub 2} capture solvents, Reversible Ionic Liquids (RevILs), that offer high absorption capacity through two modes of capture: chemical reaction (chemisorption) and physical solubility (physisorption). These solvents are silicon containing alkaline compounds such as silylamines that form a liquid salt (ionic liquid) upon reaction with CO{sub 2}. Subsequently, modest elevations in temperature reverse the reaction and yield pure CO{sub 2} for sequestration. By incorporating Si in the molecules we have reduced the viscosity, thereby improving the mass transfer rates of CO{sub 2} absorption/desorption and decreasing the processing costs for pumping the solvent. In this project, we have made systematic changes to the structure of these compounds to improve several physical and thermodynamic properties important for CO{sub 2} capture. Through these structure-property paradigms, we have obtained a RevIL which requires only a third of the energy required by conventional aqueous MEA process for 90% CO{sub 2} capture.

  6. The reverse double standard in perceptions of student-teacher sexual relationships: the role of gender, initiation, and power.

    Science.gov (United States)

    Howell, Jennifer L; Egan, Patrick M; Giuliano, Traci A; Ackley, Braden D

    2011-01-01

    The present study tested the prediction that male teachers are judged more harshly than female teachers for engaging in heterosexual intercourse with a student. One-hundred and eighty-seven adults (116 women, 71 men) evaluated a hypothetical newspaper article describing an alleged student-teacher relationship as part of a 2 (Gender Dyad: Male Teacher/Female Student or Female Teacher/Male Student) x 2 (Initiator: Student or Teacher) between-subjects design. As expected, a reverse sexual double standard was revealed, in which participants judged situations involving male teachers more harshly than they judged situations involving female teachers, but only when the sexual contact was teacher-initiated. Participants also believed that male students received more social benefits from the sexual contact than did female students.

  7. Bactericidal Effect of Lauric Acid-Loaded PCL-PEG-PCL Nano-Sized Micelles on Skin Commensal Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Thi-Quynh-Mai Tran

    2016-08-01

    Full Text Available Acne is the over growth of the commensal bacteria Propionibacterium acnes (P. acnes on human skin. Lauric acid (LA has been investigated as an effective candidate to suppress the activity of P. acnes. Although LA is nearly insoluble in water, dimethyl sulfoxide (DMSO has been reported to effectively solubilize LA. However, the toxicity of DMSO can limit the use of LA on the skin. In this study, LA-loaded poly(ɛ-caprolactone-poly(ethylene glycol-poly(ɛ-caprolactone micelles (PCL-PEG-PCL were developed to improve the bactericidal effect of free LA on P. acnes. The block copolymers mPEG-PCL and PCL-PEG-PCL with different molecular weights were synthesized and characterized using 1H Nuclear Magnetic Resonance spectroscopy (1H NMR, Fourier-transform infrared spectroscopy (FT-IR, Gel Permeation Chromatography (GPC, and Differential Scanning Calorimetry (DSC. In the presence of LA, mPEG-PCL diblock copolymers did not self-assemble into nano-sized micelles. On the contrary, the average particle sizes of the PCL-PEG-PCL micelles ranged from 50–198 nm for blank micelles and 27–89 nm for LA-loaded micelles. The drug loading content increased as the molecular weight of PCL-PEG-PCL polymer increased. Additionally, the minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC of free LA were 20 and 80 μg/mL, respectively. The MICs and MBCs of the micelles decreased to 10 and 40 μg/mL, respectively. This study demonstrated that the LA-loaded micelles are a potential treatment for acne.

  8. (PCL/AA) hydrogel for controlled drug delivery

    Indian Academy of Sciences (India)

    Administrator

    acrylic acid (PCL/AA) hydrogels have been developed using ethylene glycol dimethacrylate (EGDMA) as a cross-linker and benzoyl peroxide as initiator. For these prepared hydrogels swelling studies, sol–gel fraction analysis and porosity.

  9. Well-defined ABA- and BAB-type block copolymers of PDMAEMA and PCL

    DEFF Research Database (Denmark)

    Bruce, Carl; Javakhishvili, Irakli; Fogelstrom, Linda

    2014-01-01

    Triblock copolymers of ABA- and BAB-type consisting of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, A) and poly(epsilon-caprolactone) (PCL, B) have successfully been prepared. PDMAEMA-b-PCL-b-PDMAEMA (ABA) and PCL-b-PDMAEMA-b-PCL (BAB) were synthesised by a combination of ring...... as the outer block (ABA), the inherent crystallinity of PCL was destroyed while with PCL as the outer block (BAB), the degree of crystallinity was in the same proximity as for a PCL homopolymer....

  10. Organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides with intercalated phacolysin as ocular delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhiguo; Zhang, Jie; Chi, Huibo; Cao, Feng, E-mail: cpufengc@163.com [China Pharmaceutical University, Department of Pharmaceutics, School of Pharmacy (China)

    2015-12-15

    This study was mainly aimed to evaluate the potential use of a novel ocular drug delivery system, organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides (LDH). Organic polymers of chitosan–glutathione (CG) and pre-activated chitosan–glutathione (CG-2MNA) were successfully synthesized and characterized. LDH with intercalated phacolysin (PCL), including larger hexagonal LDH–PCL (Lh-LDH–PCL), larger spherical LDH–PCL (Ls-LDH–PCL), smaller hexagonal LDH–PCL (Sh-LDH–PCL), CG hybrid LDH–PCL (LDH–PCL-CG), and CG-2MNA hybrid LDH–PCL (LDH–PCL-CG-2MNA), were prepared. The nanocomposites with particle size of 107.2–274.9 nm were characterized by powder X-ray diffraction, Fourier transform infrared, transmission electron micrographs, etc. In vivo precorneal retention studies showed that the detectable time of all nanocomposites was prolonged from 2 to 6 h in comparison to PCL saline. Accordingly, the AUC{sub 0–6h} values of Lh-LDH–PCL, Ls-LDH–PCL, Sh-LDH–PCL, LDH–PCL-CG, and LDH–PCL-CG-2MNA nanocomposites were increased by 2.27-, 2.08-, 3.08-, 4.67-, and 3.36-fold, respectively. The Draize test and hematoxylin and eosin staining demonstrated that modified LDH had no eye irritation after single and repeated administration. These results indicated that chitosan derivatives-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs.Graphical AbstractThiolated chitosan-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs and may facilitate penetration of drugs into tissues of the eyes.

  11. A randomized, placebo-controlled, double-blind study to confirm the reversal of hepatorenal syndrome type 1 with terlipressin: the REVERSE trial design

    Directory of Open Access Journals (Sweden)

    Boyer TD

    2012-07-01

    Full Text Available Thomas D Boyer,1 Joseph J Medicis,2 Stephen Chris Pappas,3 Jim Potenziano,2 Khuramm Jamil21Department of Medicine, University of Arizona College of Medicine, Tucson, AZ, USA; 2Research and Development, Ikaria, Hampton, NJ, USA; 3Orphan Therapeutics, Lebanon, NJ, USABackground: Hepatorenal syndrome (HRS is a rare disorder of marked renal dysfunction in patients with cirrhosis, ascites, and portal hypertension. Type 1 HRS is a rapidly progressive acute kidney injury that develops shortly after a precipitating event, followed by a deterioration of function of other organs (eg, heart, brain, liver, adrenal glands. Presently, no approved drug therapies exist for HRS type 1 in the USA, Canada, or Australia. Given the rarity of this condition and the existing unmet medical need for treatment, the US Food and Drug Administration granted orphan drug and fast-track designations for terlipressin. The objective of the REVERSE trial was to determine the efficacy and safety of intravenous terlipressin compared with placebo in the treatment of adults with HRS type 1 who were also receiving intravenous albumin.Methods: 180 subjects with HRS type 1 were enrolled at 65 investigational sites located in the USA and ten sites in Canada. Patients were randomized in a 1:1 ratio to treatment with either intravenous terlipressin administered every 6 hours or placebo for up to 14 days. The primary efficacy measure was confirmed HRS reversal, defined as the percentage of patients with two serum creatinine values of ≤1.5 mg/dL at least 48 hours apart, on treatment, and without intervening renal replacement therapy or liver transplantation. Other efficacy measures included change in renal function as reflected in serum creatinine levels, fractional excretion of sodium, recurrence of HRS type 1, transplant-free, dialysis-free, and overall survival.Discussion: Data from this pivotal study are intended to demonstrate whether terlipressin is effective in reversing HRS type 1

  12. Augmentation or reconstruction of PCL? A quantitative review.

    Science.gov (United States)

    Del Buono, Angelo; Radmilovic, Juri; Gargano, Giuseppe; Gatto, Salvatore; Maffulli, Nicola

    2013-05-01

    The purpose of this quantitative review is to document effectiveness and complications of posterior cruciate ligament (PCL) surgery and compare outcomes, advantages and disadvantages of reconstructive and augmentation procedures. A systematic literature search was performed in PubMed, Medline, Ovid, Google Scholar and Embase databases using the combined keywords "PCL reconstruction," "PCL augmentation," "clinical outcomes" and "functional outcomes" with no limit for year of publication. Articles were included if they reported data on clinical, functional and imaging outcomes who had undergone reconstruction or augmentation of the PCL for management of PCL injuries. Two authors screened the selected articles for title, abstract and full text in accordance with predefined inclusion and exclusion criteria. The methodological quality of all articles was assessed by two authors according to the Coleman methodology score. The critical appraisal was made using the Physiotherapy Evidence Database (PEDro) scale. A total of 34 studies, 22 retrospective, 9 prospective and 5 were randomized control trials were included by full text. The modified Coleman methodology score averaged 70.8 (SD 6.5), median 73 (range from 60 to 82). At IKDC assessment, the average rate of normal (A) and nearly normal (B) outcomes was 89.8% (SD 4.2) (from 85 to 93%; median 91.4) after PCL augmentation and 80.1% (SD 12.4) after PCL reconstruction (from 57.2 to 100%; median 81.8 %) were rated as normal (A) and nearly normal (B). The average Lysholm Knee Scores after PCL augmentation were 93.1 points (SD 1.9) and ranged from 82.1 to 94.2 (median 90.5) after PCL reconstruction. The KT 1000 difference improved from an average preoperative difference of 8.8 mm (SD 0.9) to an average postoperative of 2.1 mm (SD 0.6) after PCL augmentation (average improvement of 6.7 mm (SD 4.7)) and from 8.2 (SD 3.6) to 2.3 mm (SD 2.0) (average improvement of 5.9 mm SD 4.2) after PCL reconstruction. Postoperatively, the

  13. A case report of Schatzker type VI tibial plateau fracture treated with double reverse traction closed reduction combined with minimally invasive percutaneous plate osteosynthesis technique: A case report.

    Science.gov (United States)

    Li, Dian-Qing; Song, De-Ye; Ni, Jiang-Dong; Ding, Mu-Liang; Huang, Jun

    2017-11-01

    The knee joint is an important weight-bearing joint, tibial plateau fractures affect knee function and stability. High-energy intra-articular fractures involving the tibial plateau can cause management-related problems such as wound dehiscence; severe comminution leading to malalignment; and delayed complications such as varus collapse, implant failure, and arthritis of the knee joint. The treatment of severe or complex tibial plateau fractures can be quite difficult. Traditional methods of open reduction and plating require extensive exposures, which may further compromise soft tissue and devascularize bone fragments, leading to infection. In this case, a novel device, double reverse traction combined with MIPPO technique, was used and provided the possibility of minimally invasive and personalized orthopedic surgery to treat severe comminuted Schatzker type VI tibial plateau fracture and tibial shaft fracture and got satisfactory results. A previously healthy 56-year-old man presented to the emergency room after a fall from a height, who lost the movement of the left knee with pain and swelling. X-rays showed a tibial plateau comminuted fracture, Schatzker type VI, and tibial shaft fracture. Applying less extensile exposure and the indirect reduction technique of double reverse traction and closed reduction combined with minimally invasive percutaneous plate osteosynthesis (MIPPO) technique, we got satisfactory recovery of the severe comminuted Schatzker type VI tibial plateau fracture and tibial shaft fracture. This severe comminuted fracture and tibial shaft fracture were successfully reduced and got satisfactory recovery of knee joint function. Double reverse traction combined with MIPPO technique can reduce the risk of surgical complications, such as bleeding, oozing, and wound infection. It can be applied in patients with comorbidities such as cardiac disease, hypertension, and heart failure who may otherwise not be candidates for surgery. The cost burden is

  14. Polysaccharide-coated PCL nanofibers for wound dressing applications.

    Science.gov (United States)

    Croisier, Florence; Atanasova, Ganka; Poumay, Yves; Jérôme, Christine

    2014-12-01

    Polysaccharide-based nanofibers with a multilayered structure are prepared by combining electrospinning (ESP) and layer-by-layer (LBL) deposition techniques. Charged nanofibers are firstly prepared by electrospinning poly(ε-caprolactone) (PCL) with a block-copolymer bearing carboxylic acid functions. After deprotonation of the acid groups, the layer-by-layer deposition of polyelectrolyte polysaccharides, notably chitosan and hyaluronic acid, is used to coat the electrospun fibers. A multilayered structure is achieved by alternating the deposition of the positively charged chitosan with the deposition of a negatively charged polyelectrolyte. The construction of this multilayered structure is followed by Zeta potential measurements, and confirmed by observation of hollow nanofibers resulting from the dissolution of the PCL core in a selective solvent. These novel polysaccharide-coated PCL fiber mats remarkably combine the mechanical resistance typical of the core material (PCL)-particularly in the hydrated state-with the surface properties of chitosan. The control of the nanofiber structure offered by the electrospinning technology, makes the developed process very promising to precisely design biomaterials for tissue engineering. Preliminary cell culture tests corroborate the potential use of such system in wound healing applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Passive Posterior Tibial Subluxation on Routine Knee MRI as a Secondary Sign of PCL Tear

    OpenAIRE

    Andrew J. Degnan; Catherine Maldjian; Richard J. Adam; Christopher D. Harner

    2014-01-01

    The posterior drawer test is an accurate clinical test to diagnose posterior cruciate ligament (PCL), indicating laxity of the PCL that allows posterior tibial translation. This study aimed to determine whether posterior tibial translation relative to the femur on routine MRI could serve as an additional sign of PCL tear. Routine knee MRI in eleven patients (7 males, 4 females) with arthroscopically confirmed isolated PCL tears were reviewed independently by two musculoskeletal radiologists. ...

  16. Electrospun PVA-PCL-HAB scaffold for craniofacial bone regeneration

    DEFF Research Database (Denmark)

    Prabha, Rahul; Kraft, David Christian Evar; Melsen, Birte

    2015-01-01

    body fluid immersed scaffold samples. Culturing human adult dental pulp stem cells (DPSC) and human bone marrow derived MSC seeded on PVA-PCL-HAB scaffold showed enhanced cell proliferation and in vitro osteoblastic differentiation. Cell-containing scaffolds were implanted subcutaneously in immune......-caprolactone (PCL)- triphasic bioceramic(HAB) scaffold to biomimic native tissue and we tested its ability to support osteogenic differentiation of stromal stem cells ( MSC) and its suitability for regeneration of craniofa- cial defects. Physiochemical characterizations of the scaffold, including con- tact angle...... deficient mice. Histologic ex- amination of retrieved implant sections stained with H&E, Col- lagenType I and Human Vimentin antibody demonstrated that the cells survived in vivo in the implants for at least 8 weeks with evidence of osteoblastic differentiation and angiogenesis within the implants. Our...

  17. Chronic caffeine treatment reverses memory impairment and the expression of brain BNDF and TrkB in the PS1/APP double transgenic mouse model of Alzheimer's disease.

    Science.gov (United States)

    Han, Kun; Jia, Ning; Li, Ji; Yang, Li; Min, Lian-Qiu

    2013-09-01

    The objective of this study was to investigate the effects of varying doses of caffeine on memory impairment and the expression of brain neurotrophic derived factor (BNDF) and TrkB in PS1/APP double transgenic mouse models. PS1/APP double transgenic mice were administered 0.3 ml/day of saline, 1.5 mg/day of caffeine or 0.75 mg/day of caffeine for eight weeks. A water maze test and western blotting were used to determine the memory capability and expression of hippocampal BNDF and TrkB of the mice. The results demonstrated that 0.75 mg/day and 1.5 mg/day doses of caffeine significantly increased memory capability and the expression of hippocampal BDNF and TrkB in PS1/APP mice with a dose-response effect. The results suggested that chronic caffeine treatment may reverse memory impairment in PS1/APP transgenic mice, and BDNF and its receptor TrkB, may be involved in this process.

  18. 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.

  19. Functionalized PCL/HA nanocomposites as microporous membranes for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Basile, Maria Assunta; Gomez d' Ayala, Giovanna; Malinconico, Mario [Institute for Polymers, Composites and Biomaterials, CNR, Via Campi Flegrei 34, Pozzuoli (Naples) (Italy); Laurienzo, Paola, E-mail: paola.laurienzo@ipcb.cnr.it [Institute for Polymers, Composites and Biomaterials, CNR, Via Campi Flegrei 34, Pozzuoli (Naples) (Italy); Coudane, Jean; Nottelet, Benjamin [Institut des Biomolécules Max Mousseron (IBMM), Artificial Biopolymers Group, CNRS UMR 5247, University of Montpellier 1, Faculty of Pharmacy, 15 Av. C. Flahault, Montpellier 34093 (France); Ragione, Fulvio Della [Department of Biochemistry and Biophysics, Second University of Naples, Via L. De Crecchio 7, Naples (Italy); Oliva, Adriana, E-mail: adriana.oliva@unina2.it [Department of Biochemistry and Biophysics, Second University of Naples, Via L. De Crecchio 7, Naples (Italy)

    2015-03-01

    In the present work, microporous membranes based on poly(ε-caprolactone) (PCL) and PCL functionalized with amine (PCL-DMAEA) or anhydride groups (PCL-MAGMA) were realized by solvent–non solvent phase inversion and proposed for use in Guided Tissue Regeneration (GTR). Nanowhiskers of hydroxyapatite (HA) were also incorporated in the polymer matrix to realize nanocomposite membranes. Scanning Electron Microscopy (SEM) showed improved interfacial adhesion with HA for functionalized polymers, and highlighted substantial differences in the porosity. A relationship between the developed porous structure of the membrane and the chemical nature of grafted groups was proposed. Compared to virgin PCL, hydrophilicity increases for functionalized PCL, while the addition of HA influences significantly the hydrophilic characteristics only in the case of virgin polymer. A significant increase of in vitro degradation rate was found for PCL-MAGMA based membranes, and at lower extent of PCL-DMAEA membranes. The novel materials were investigated regarding their potential as support for cell growth in bone repair using multipotent mesenchymal stromal cells (MSC) as a model. MSC plated onto the various membranes were analyzed in terms of adhesion, proliferation and osteogenic capacity that resulted to be related to chemical as well as porous structure. In particular, PCL-DMAEA and the relative nanocomposite membranes are the most promising in terms of cell-biomaterial interactions. - Graphical abstract: Functionalized PCL is used to realize nanocomposites with hydroxyapatite (HA) in the form of microporous membranes. The influence of different grafted groups on mechanical properties, in vitro degradation, porous membrane structure and interaction with mesenchymal stromal cells (MSC) is discussed. - Highlights: • Functionalized PCL shows faster in vitro degradation rate. • Functionalized PCL shows superior cell adhesion, proliferation and differentiation. • Nanocomposites based

  20. Galvanostatic pulse followed by coulostatic impulse with reversed sign: A new double-pulse method for the determination of the kinetic parameters of electrode reactions I. Theory and classification

    NARCIS (Netherlands)

    Leeuwen, H.P. van; Sluyters, J.H.

    A new double pulse method is presented in which a galvanostatic pre-pulse is followed by a coulostatic impulse with reversed sign. The coulostatic charge density selected is such that the overvoltage-time curve starts with a horizontal tangent after the impulse has ceased. As both the net current

  1. Combined PCL and PLC reconstruction in chronic posterolateral instability.

    Science.gov (United States)

    Zorzi, Claudio; Alam, Mahbub; Iacono, Venanzio; Madonna, Vincenzo; Rosa, Donato; Maffulli, Nicola

    2013-05-01

    The posterolateral corner (PLC) is more likely to be injured in combination with the posterior cruciate ligament (PCL) or the anterior cruciate ligament than in isolation. This leads to instability of the knee and loss of function. We hypothesised that combined PCL and PLC reconstruction would restore sufficient stability to allow improvement in patient symptoms and function. 19 patients who underwent arthroscopic-assisted single-bundle PCL and PLC reconstruction by a single surgeon were analysed retrospectively. The PLC reconstruction was a modified Larson reconstruction of the lateral collateral ligament and the popliteofibular ligament. The IKDC and Tegner scores were used to assess outcome. Dial test and varus laxity were used to assess improvements in clinical laxity. Posterior laxity was tested using the KT-1000. The mean follow-up was 38 months (±(2× standard deviations), ±12.3). There were no postoperative complications. All patients had less than 5 mm posterior step-off. 17 of 19 patients had negative dial and varus stress tests. Measured range of motion was reduced by a mean of 10°, but patients did not report any daily activities restrictions. Tegner scores improved from a median pre-operative value of 2 (range 1-4) to 6 (4-9) at final follow-up. The mean postoperative IKDC score was 86 (±11). Subjectively, the knee stability achieved allowed daily activities. However, there were remaining abnormalities in range of motion, posterior drawer and rotational laxity, suggesting that normal knee laxity was not restored. IV.

  2. PLDLA/PCL-T Scaffold for Meniscus Tissue Engineering.

    Science.gov (United States)

    Esposito, Andrea Rodrigues; Moda, Marlon; Cattani, Silvia Mara de Melo; de Santana, Gracy Mara; Barbieri, Juliana Abreu; Munhoz, Monique Moron; Cardoso, Túlio Pereira; Barbo, Maria Lourdes Peris; Russo, Teresa; D'Amora, Ugo; Gloria, Antonio; Ambrosio, Luigi; Duek, Eliana Aparecida de Rezende

    2013-04-01

    The inability of the avascular region of the meniscus to regenerate has led to the use of tissue engineering to treat meniscal injuries. The aim of this study was to evaluate the ability of fibrochondrocytes preseeded on PLDLA/PCL-T [poly(L-co-D,L-lactic acid)/poly(caprolactone-triol)] scaffolds to stimulate regeneration of the whole meniscus. Porous PLDLA/PCL-T (90/10) scaffolds were obtained by solvent casting and particulate leaching. Compressive modulus of 9.5±1.0 MPa and maximum stress of 4.7±0.9 MPa were evaluated. Fibrochondrocytes from rabbit menisci were isolated, seeded directly on the scaffolds, and cultured for 21 days. New Zealand rabbits underwent total meniscectomy, after which implants consisting of cell-free scaffolds or cell-seeded scaffolds were introduced into the medial knee meniscus; the negative control group consisted of rabbits that received no implant. Macroscopic and histological evaluations of the neomeniscus were performed 12 and 24 weeks after implantation. The polymer scaffold implants adapted well to surrounding tissues, without apparent rejection, infection, or chronic inflammatory response. Fibrocartilaginous tissue with mature collagen fibers was observed predominantly in implants with seeded scaffolds compared to cell-free implants after 24 weeks. Similar results were not observed in the control group. Articular cartilage was preserved in the polymeric implants and showed higher chondrocyte cell number than the control group. These findings show that the PLDLA/PCL-T 90/10 scaffold has potential for orthopedic applications since this material allowed the formation of fibrocartilaginous tissue, a structure of crucial importance for repairing injuries to joints, including replacement of the meniscus and the protection of articular cartilage from degeneration.

  3. PLDLA/PCL-T Scaffold for Meniscus Tissue Engineering

    Science.gov (United States)

    Moda, Marlon; Cattani, Silvia Mara de Melo; de Santana, Gracy Mara; Barbieri, Juliana Abreu; Munhoz, Monique Moron; Cardoso, Túlio Pereira; Barbo, Maria Lourdes Peris; Russo, Teresa; D'Amora, Ugo; Gloria, Antonio; Ambrosio, Luigi; Duek, Eliana Aparecida de Rezende

    2013-01-01

    Abstract The inability of the avascular region of the meniscus to regenerate has led to the use of tissue engineering to treat meniscal injuries. The aim of this study was to evaluate the ability of fibrochondrocytes preseeded on PLDLA/PCL-T [poly(L-co-D,L-lactic acid)/poly(caprolactone-triol)] scaffolds to stimulate regeneration of the whole meniscus. Porous PLDLA/PCL-T (90/10) scaffolds were obtained by solvent casting and particulate leaching. Compressive modulus of 9.5±1.0 MPa and maximum stress of 4.7±0.9 MPa were evaluated. Fibrochondrocytes from rabbit menisci were isolated, seeded directly on the scaffolds, and cultured for 21 days. New Zealand rabbits underwent total meniscectomy, after which implants consisting of cell-free scaffolds or cell-seeded scaffolds were introduced into the medial knee meniscus; the negative control group consisted of rabbits that received no implant. Macroscopic and histological evaluations of the neomeniscus were performed 12 and 24 weeks after implantation. The polymer scaffold implants adapted well to surrounding tissues, without apparent rejection, infection, or chronic inflammatory response. Fibrocartilaginous tissue with mature collagen fibers was observed predominantly in implants with seeded scaffolds compared to cell-free implants after 24 weeks. Similar results were not observed in the control group. Articular cartilage was preserved in the polymeric implants and showed higher chondrocyte cell number than the control group. These findings show that the PLDLA/PCL-T 90/10 scaffold has potential for orthopedic applications since this material allowed the formation of fibrocartilaginous tissue, a structure of crucial importance for repairing injuries to joints, including replacement of the meniscus and the protection of articular cartilage from degeneration. PMID:23593566

  4. Reparation and characterization of water-borne polyurethane based on PCDL or (and) PCL prepolymer

    Science.gov (United States)

    Sun, Yenan; Zhao, Can; Xiao, Jijun

    2017-08-01

    A series of waterborne polyurethanes (WPUs) were synthesized by a pre-polymer process from isophorone diisocyanate and polycarbonatediol (PCDL), polycaprolactone (PCL). Fourier transform infrared spectroscopy, thermal gravimetric analysis, dynamic thermomechanical analysis and mechanical measurements were employed to characterize the thermal stability, physical and mechanical properties of the films derived from the emulsions. The results show that there is better mechanical properties of and thermal stability for PCL-based WPU. The thermal stability of PCDL-PCL based WPU, whichin the mass ratio of PCDL to PCL is 1 to 1 is the best. The PCDL-based WPU has the highest glass transition temperature.

  5. Data of PCL-b-P(MMA-DMAEMA)2characterization and related assays.

    Science.gov (United States)

    Franco, Camila; Barcelos Antonow, Michelli; Beckenkamp, Aline; Buffon, Andréia; Ceolin, Taise; Luiza Tebaldi, Marli; Pozza Silveira, Gustavo; Stanisçuaski Guterres, Silvia; Raffin Pohlmann, Adriana

    2017-12-01

    The data presented here are related to the research paper entitled "PCL- b -P(MMA- co -DMAEMA) 2 new triblock copolymer for novel pH-sensitive nanocapsules intended for drug delivery to tumors" by Franco et al. [1]. Characterization data of PCL-diol, macroinitiator Br-PCL-Br, homopolymers (PMMA and PDMAEMA) and copolymers (batch 1 and batch 2) analyzed by FTIR, SEC and NMR, as well as, characterization of PCL-NS formulation by laser diffraction and DLS analysis, initial nanocapsule formulations and 1 C -NC and 2 C -NC formulations, including hydrodynamic diameter at different pH media, and DMSO cytotoxicity.

  6. Preparation of novel functional Mg/O/PCL/ZnO composite biomaterials and their corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Zhongxian; Tan, Cui; Xu, Lan; Yang, Na; Li, Qing, E-mail: liqingdswu@163.com

    2015-10-01

    Highlights: • Novel functional Mg/O/PCL/ZnO composite biomaterials were prepared. • The biomaterials were prepared by anodization treatment and dip-coating technique. • The composite biomaterials were smooth and with low porosity. • The prepared biomaterials have good corrosion resistance in SBF. • The composite biomaterials can release zinc ion to promote bone formation. - Abstract: In this study, novel and functional Mg/O/PCL/ZnO (magnesium/anodic film/poly(ε-caprolactone)/zinc oxide) composite biomaterials for enhancing the bioactivity and biocompatibility of the implant was prepared by using anodization treatment and dip-coating technique. The surface morphology, microstructure, adhesion strength and corrosion resistance of the composite biomaterials were investigated using scanning electron microscopy (SEM), adhesion measurements, electrochemical tests and immersion tests respectively. In addition, the biocompatible properties of Mg (magnesium), Mg/PCL (magnesium/poly(ε-caprolactone)) and Mg/O/PCL (magnesium/anodic film/poly(ε-caprolactone)) samples were also investigated. The results show that the Mg/O/PCL/ZnO composite biomaterials were with low porosity and with the ZnO powders dispersed in PCL uniformly. The adhesion tests suggested that Mg/O/PCL/ZnO composite biomaterials had better adhesion strength than that of Mg/PCL composite biomaterials obviously. Besides, an in vitro test for corrosion demonstrated that the Mg/O/PCL/ZnO composite biomaterials had good corrosion resistance and zinc ion was released obviously in SBF.

  7. A case report of Warthin's tumor (Papillary cystadenoma lymphomatosum, PCL

    Directory of Open Access Journals (Sweden)

    Agha Hosseini F

    1993-04-01

    Full Text Available The papillary cystadenoma lymphomatosum (PCL, also called warthin's tumor, is a benign salivary gland tumor which primarily involves the parotid gland. These lesions are composed of a double layer of cuboidal or culmnar eosinophilic cells lining a cystic cavity which lymphoid tissue is present in the supporting stroma. The lesions shows a predilection for males, with peak incidence during the sixth decade of life. Bilateral lesions have been found to occur in 5 to 7.5 percent of the cases. Rarely, these lesions have been reported in the minor salivary glands and oropharynx. Case report: A 47-year-old woman presented with a red lesion on the hard palate between the midline and right maxillary side. The patient had awared of the lesion for one year. The clinical dignosis was a mucocele. An excisional biopsy was performed. Gross examination of the formaline-fixed specimen revealed three pieces of soft tissue measuring 1.0 x 0.3 x 0.3. Histologic examination revealed a nodular mass surfaced by keratinizied stratified squamous epithelium. The connective tissue stroma contained a papillary cystic area lined by a double layer of cuboidal cells with centrally placed nuclei

  8. Synthesis and Characterization of Chrysin-loaded PCL-PEG-PCL nanoparticle and its effect on breast cancer cell line.

    Science.gov (United States)

    Eatemadi, Ali; Daraee, Hadis; Aiyelabegan, Hammed T; Negahdari, Babak; Rajeian, Bahram; Zarghami, Nosratollah

    2016-12-01

    Nano-therapy exhibit the potential of revolutionizing cancer therapy. This field introduces nanovectors/nanocarriers for anticancer drugs targeted delivery, and also finds application in imaging. Chrysin, a natural flavonoid, was recently studied as having important biological roles in chemical defenses, nitrogen fixation, anti-inflammatory, and anti-oxidant properties. We aim at studying the effect of nano-chrysin on breast cancer cell line. The effect of chrysin loaded PCL-PEG-PCL was studied on T47D breast cancer cell line. The structure and drug-loading of chrysin were characterized using (1)H NMR, FT-IR and SEM. The in vitro cytotoxicity of pure and nano-chrysin was tested by the MTT assay. Gene expression of FTO, hTERT, and BRCA1 were evaluated using Real-time PCR. Data analysis from MTT assay showed that chrysin has a time-dependent cytotoxic effect on T47D cell line. Furthermore, the results of Real-time PCR suggested that encapsulated chrysin have higher antitumor effect on gene expression of FTO, BRCA1 and hTERT than free chrysin. Combined nano-chrysin therapy will not only improve cancer cell cytotoxicity, but also be a complementary and potential complex in breast cancer therapy. Copyright © 2016. Published by Elsevier Masson SAS.

  9. Laser Printing of PCL/Progesterone Tablets for Drug Delivery Applications in Hormone Cancer Therapy

    Science.gov (United States)

    Salmoria, G. V.; Klauss, P.; Kanis, L. A.

    2017-09-01

    In this study, polycaprolactone (PCL) and progesterone (PG) tablets were produced by selective laser sintering (SLS) using different particle sizes and laser energy. The sintered PCL/PG tablets presented uniform morphology, coalescence of particles and interconnected pores distributed in the polymeric matrix. The EDS analysis confirmed the presence of progesterone recrystallized on the surface of the porous PCL matrix. The crystallinity values for the PCL/PG tablets were lower than that for the pure PCL, suggesting the interaction of components at the molecular level. The PCL/PG tablets fabricated with small particles and high laser energy presented a higher value for the flexural modulus compared with the other specimens. The glass transition temperature (Tg) was -37 °C for the PCL/PG tablet with a high degree of sintering. The fatigue test showed that the PCL/PG blend tablets have high fatigue strength. The drug release mechanism of all tablets studied followed a zero-order kinetics, and drug release rates were dependent on sintering degree and, consequently, on matrix erosion, showing a potential application to controlled drug delivery in hormone cancer therapy.

  10. Guided-Inquiry Experiments for Physical Chemistry: The POGIL-PCL Model

    Science.gov (United States)

    Hunnicutt, Sally S.; Grushow, Alexander; Whitnell, Robert

    2015-01-01

    The POGIL-PCL project implements the principles of process-oriented, guided-inquiry learning (POGIL) in order to improve student learning in the physical chemistry laboratory (PCL) course. The inquiry-based physical chemistry experiments being developed emphasize modeling of chemical phenomena. In each experiment, students work through at least…

  11. Factor Structure of the Hare Psychopathy Checklist: Youth Version (PCL: YV) in Incarcerated Adolescents

    Science.gov (United States)

    Neumann, Craig S.; Kosson, David S.; Forth, Adelle E.; Hare, Robert D.

    2006-01-01

    Two studies are reported on the underlying dimensions of the psychopathy construct in adolescents as measured by the Hare Psychopathy Checklist-Youth Version (PCL: YV; Forth, Kosson, & Hare, 2003). In Study 1, the PCL: YV item ratings for 505 male adolescents incarcerated in 5 different settings in North America were used to test the fit of 3…

  12. Design, construction and mechanical testing of digital 3D anatomical data-based PCL-HA bone tissue engineering scaffold.

    Science.gov (United States)

    Yao, Qingqiang; Wei, Bo; Guo, Yang; Jin, Chengzhe; Du, Xiaotao; Yan, Chao; Yan, Junwei; Hu, Wenhao; Xu, Yan; Zhou, Zhi; Wang, Yijin; Wang, Liming

    2015-01-01

    The study aims to investigate the techniques of design and construction of CT 3D reconstructional data-based polycaprolactone (PCL)-hydroxyapatite (HA) scaffold. Femoral and lumbar spinal specimens of eight male New Zealand white rabbits were performed CT and laser scanning data-based 3D printing scaffold processing using PCL-HA powder. Each group was performed eight scaffolds. The CAD-based 3D printed porous cylindrical stents were 16 piece × 3 groups, including the orthogonal scaffold, the Pozi-hole scaffold and the triangular hole scaffold. The gross forms, fiber scaffold diameters and porosities of the scaffolds were measured, and the mechanical testing was performed towards eight pieces of the three kinds of cylindrical scaffolds, respectively. The loading force, deformation, maximum-affordable pressure and deformation value were recorded. The pore-connection rate of each scaffold was 100 % within each group, there was no significant difference in the gross parameters and micro-structural parameters of each scaffold when compared with the design values (P > 0.05). There was no significant difference in the loading force, deformation and deformation value under the maximum-affordable pressure of the three different cylinder scaffolds when the load was above 320 N. The combination of CT and CAD reverse technology could accomplish the design and manufacturing of complex bone tissue engineering scaffolds, with no significant difference in the impacts of the microstructures towards the physical properties of different porous scaffolds under large load.

  13. Psychopathy, PCL-R, and MAOA genotype as predictors of violent reconvictions.

    Science.gov (United States)

    Tikkanen, Roope; Auvinen-Lintunen, Laura; Ducci, Francesca; Sjöberg, Rickard L; Goldman, David; Tiihonen, Jari; Ojansuu, Ilkka; Virkkunen, Matti

    2011-02-28

    The Revised Psychopathy Checklist (PCL-R) has shown a moderate association with violence. The efficacy of PCL-R in varying monoamine oxidase A (MAOA) genotypes is, however, unexamined. The aim of this study was to investigate the effect of PCL-R and psychopathy on the risk for violent reconvictions among 167 MAOA genotyped alcoholic offenders. Violent reconvictions and PCL-R scores among violent offenders were assessed after a 7-year non-incarcerated follow-up. Regression analysis was used to evaluate the alcohol exposure and age-adjusted effect of PCL-R score and psychopathy on the risk for reconvictions among differing MAOA genotypes. Results suggest that the PCL-R total score predicts impulsive reconvictions among high-activity MAOA offenders (6.8% risk increase for every one-point increase in PCL-R total score, P = 0.015), but not among low-activity MAOA offenders, whereas antisocial behavior and attitudes predicted reconvictions in both genotypes (17% risk increase among high-activity MAOA offenders and 12.8% increase among low-activity MAOA offenders for every one-point increase in factor 2 score). Both narcissistic self-image with related interpersonal style (factor 1 score) and psychopathy (PCL-R ≥ 30) failed to predict future violence. Results suggest that the efficacy of PCL-R is altered by MAOA genotype, alcohol exposure, and age, which seems important to note when PCL-R is used for risk assessments that will have legal or costly preventive work consequences. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Efficient cutaneous wound healing using bixin-loaded PCL nanofibers in diabetic mice.

    Science.gov (United States)

    Pinzón-García, Ana Delia; Cassini-Vieira, Puebla; Ribeiro, Cyntia Cabral; de Matos Jensen, Carlos Eduardo; Barcelos, Luciola Silva; Cortes, Maria Esperanza; Sinisterra, Ruben Dario

    2017-10-01

    The present work demonstrated an efficient cutaneous wound healing using Bixin-loaded polycaprolactone (PCL) nanofibers as a controlled delivery system. The influence of Bixin (Bix) content on PCL nanofiber, Bix-PCL1(2.5% w/w bix) and Bix-PCL2 (12.5% w/w bix) formation was investigated using electrical conductivity, attenuated total reflectance infrared spectroscopy, X-ray diffraction, thermal analysis, and scanning electronic microscopy. The results showed that a greater bixin concentration resulted in higher polymeric solution electrical conductivity. Moreover, higher polymeric solution electrical conductivity provides lower nanofibers in terms of average diameter than pure PCL nanofibers. In vitro release was largely governed by a diffusion-controlled mechanism. The initial Bixin release domain showed a burst release over the first 10 hours where approximately 30% and 40% of Bixin was released from Bix-PCL1 and Bix-PCL2 nanofibers, respectively. The second kinetic domain was comprised of a continuous and slow Bixin release that led to almost 100% of the Bixin being released within 14 days. The results on excisional wound model in induced diabetic mice indicated that the low concentration of Bixin released from loaded Bix-PCL nanofibers maintain the biological activity of Bixin and is efficient in accelerating the wound healing as well as in reducing the scar tissue area compared with pure PCL nanofibers. Therefore, soft material Bixin-loaded PCL nanofibers are a promising candidate for use in wound dressing. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1938-1949, 2017. © 2016 Wiley Periodicals, Inc.

  15. Characterization and Mechanical Analysis of PCL/PLA composites for FDM feedstock filament

    Science.gov (United States)

    Haq, Reazul Haq Abdul; Nasrull Abdol Rahman, Mohd; Mubarak Tajul Ariffin, Ahmad; Fahrul Hassan, Mohd; Zaini Yunos, Muhamad; Adzila, Sharifah

    2017-08-01

    In this research, characterization, and the mechanical properties of Polycaprolactone (PCL) and Polylactic Acid (PLA) composites with the objective of determining their suitability as biomaterials for an alternative composites material for Fused Deposition Modelling (FDM) was investigated. The percentage of PLA is varies from 10% to 50% by weight. The PCL/PLA composites were prepared by melting and mixing using Brabender Plastograph machine. The characterization of PCL/PLA composites was characterized using Fourier Transform Infrared (FTIR). Meanwhile, the mechanical properties were evaluated are the Tensile, Flexural and Impact. It demonstrate that by the addition of PLA it improve the mechanical properties of PCL and leads to a better processability of PCL/PLA composites. With the decrement of PLA content in PCL/PLA composites the Tensile Strength the Young’s Modulus and also the Impact Strength of the composites increased. The highest tensile strength was recorded at 10.00 Mpa and the Young’s Modulus was recorded at 118.26 Mpa. The highest Impact Strength was recorded at 1.33 J. However, the Flexural Strength and Flexural Modulus increased when the content of PLA decrease and it slightly drop when the content of PLA is at the 40%. The highest Flexural Strength and Flexural Modulus were recorded at 7.59 Mpa and 35.33 Mpa respectively. Overall it can be concluded that the PCL70PLA30 composites are the best formulation and it gives a better mechanical properties result.

  16. Assessment of Morphology, Activity, and Infiltration of Astrocytes on Marine EPS-Imbedded Electrospun PCL Nanofiber

    Directory of Open Access Journals (Sweden)

    Seul Ki Min

    2014-01-01

    Full Text Available Tissue engineering using a biomaterial including bioactive compounds has been researched as a way to restore injured neural systems. Extracellular polymeric substances (EPS extracted from marine seaweeds have been known to produce positive effects on physiological activities in human tissues. In this study, an electrospun nanofiber containing brown seaweed EPS was proven to be a candidate biomaterial for neural tissue engineering. Glial fibrillary acidic protein (GFAP as a specific marker protein increased in the astrocytes cultured on the polycaprolactone (PCL nanofiber containing EPS (EPS-PCL nanofiber, compared with PCL nanofiber. The upregulation of GFAP indicates that the EPS-PCL nanofiber induced astrocyte activation, which supports physiological agents favorable to restore injured neural tissue. Astrocytes could infiltrate into the EPS-PCL nanofiber mat without toxicity, comparable to PCL nanofiber. These results imply that EPS-PCL nanofiber could be a useful biomaterial to regulate astrocyte activity at a molecular level and could be considered as a novel therapeutic material for neural tissue engineering.

  17. Fluorescent nanogel based on four-arm PEG–PCL copolymer with porphyrin core for bioimaging

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xia; Wei, Chang; Lu, Li; Liu, Tianjun; Lv, Feng, E-mail: lvfeng2002@163.com

    2016-04-01

    Four-arm PEG–PCL copolymer with porphyrin core (POR–PEG–PCL) exhibits beneficial fluorescence ability in vivo. To further develop an application of thermosensitive porphyrin hydrogel based on four-arm PEG–PCL copolymer as a drug carrier, a POR–PEG–PCL nanogel was tracked and located to tumor tissue with porphyrin as a fluorescence tag via intravenous injection. The structure and function of the nanogel were evaluated by TEM, DLS, H-NMR, UV–vis and fluorescence spectra. The fluorescent nanogel was monitored by an in vivo imaging system with hepatoma tumor-bearing mice. Good biocompatibility and safety in vitro and in vivo show that the POR–PEG–PCL nanogel is a potential drug carrier that targets tumor tissues with fluorescence bioimaging. - Highlights: • POR–PEG–PCL nanogel was developed to imaging for hepatoma tumor with porphyrin as a fluorescence tag. • Fluorescence imaging can be obviously tracked and located to tumor tissue by in vivo imaging system. • POR–PEG–PCL nanogels maybe become a novel drug carrier due to the combination of nano-size, hydrogel and fluorescence.

  18. The effect of a hydroxyapatite impregnated PCL membrane in rat subcritical calvarial bone defects.

    Science.gov (United States)

    Groppo, Monica Feresini; Caria, Paulo Henrique; Freire, Alexandre Rodrigues; Figueroba, Sidney R; Ribeiro-Neto, Wilson Alves; Bretas, Rosario Elida Suman; Prado, Felippe Bevilacqua; Haiter-Neto, Francisco; Aguiar, Flavio Henrique; Rossi, Ana Claudia

    2017-10-01

    The present study evaluated the effect of polymeric-nanofibers membranes impregnated with microparticulate hydroxyapatite (HA) in the subcritical calvarial bone defects (SCBD) healing. PCL membranes with and without HA were obtained by electrospinning. SCBD were perforated (3.3mm) in left and right sides of 36 rat calvarias. The right-side SBCD of 18 animals was filled with HA mixed with blood clot and blood clot at the contralateral side. The remaining animals received PCL+HA membrane at the right-side SCBD and PCL membrane at the contralateral side. Animals were killed after 30, 60 and 90days after surgery. Bone defect volume (in mm3) was measured by tomography (CBCT). Qualitative histological analysis and SBCD area (in mm2) were measured. Quantitative data were submitted to Kruskal-Wallis/Dunn tests. Reduction of SBCD volume was observed in all treatments but PCL. Association with HA significantly improved bone healing induced by PCL and blood clot. PCL+HA induced the lowest SBCD volume at 60 and 90days. Complete bone healing was not observed even at 90days in SCBD treated with blood clot. In every period, more bone formation was observed for SCBD treated with membranes. We concluded that both PCL membrane and HA were able to improve bone healing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The Fabrication and Characterization of PCL/Rice Husk Derived Bioactive Glass-Ceramic Composite Scaffolds

    OpenAIRE

    Farnaz Naghizadeh; Naznin Sultana; Mohammed Rafiq Abdul Kadir; Tengku Muzaffar Tengku Md Shihabudin; Rafaqat Hussain; Tunku Kamarul

    2014-01-01

    The present study was conducted to fabricate a 3D scaffold using polycaprolactone (PCL) and silicate based bioactive glass-ceramic (R-SBgC). Different concentrations of R-SBgC prepared from rice husk ash (RHA) were combined with PCL to fabricate a composite scaffold using thermally induced phase separation (TIPS) method. The products were then characterized using SEM and EDX. The results demonstrated that R-SBgC in PCL matrix produced a bioactive material which has highly porous structure wit...

  20. Epoxy/PCL nanocomposites: Effect of layered silicate on structure and behavior

    Directory of Open Access Journals (Sweden)

    J. Rotrekl

    2012-12-01

    Full Text Available The effect of clay-induced morphological transitions on the structure formed in the course of reactively induced phase separation (RIPS and its impact on the properties of epoxy/polycaprolactone (PCL nanocomposites were studied. The effect of organophilized montmorillonite on the behavior of epoxy containing 5–30% PCL was strongly dependent on the epoxy/PCL system composition. With a supercritical 20% PCL content, the increasing amounts of clay led to changes in the morphology that produced phase inversion, causing radical changes in the mechanical behavior. The main effect of the clay, which was located preferentially in the epoxy, was to influence the significant dynamic asymmetry (and thus the phase behavior. The simultaneous pinning effect of the clay on the phase separation changed the composition and parameters of the coexisting phases. The evaluation of the structure-properties relationship indicated the significant potential for nanoclays to control the behavior of thermoplastic- modified epoxy systems.

  1. Control of nanostructures in PVA, PVA/chitosan blends and PCL ...

    Indian Academy of Sciences (India)

    ... distribution of poly(caprolactone) (PCL) were also fabricated using a modified electrospinning setup. Nanofibrous microporous PVA scaffolds were fabricated using a cryogenic grinding method with subsequent compaction. Such multiscale porous structures would offer ideal matrices for tissue engineering applications.

  2. Data of PCL-b-P(MMA-DMAEMA2 characterization and related assays

    Directory of Open Access Journals (Sweden)

    Camila Franco

    2017-12-01

    Full Text Available The data presented here are related to the research paper entitled “PCL-b-P(MMA-co-DMAEMA2 new triblock copolymer for novel pH-sensitive nanocapsules intended for drug delivery to tumors” by Franco et al. [1]. Characterization data of PCL-diol, macroinitiator Br-PCL-Br, homopolymers (PMMA and PDMAEMA and copolymers (batch 1 and batch 2 analyzed by FTIR, SEC and NMR, as well as, characterization of PCL-NS formulation by laser diffraction and DLS analysis, initial nanocapsule formulations and 1C-NC and 2C-NC formulations, including hydrodynamic diameter at different pH media, and DMSO cytotoxicity. Keywords: Methacrylic copolymer, Polycaprolactone, Nanocapsules, pH-sensitive, Cell viability

  3. Small-diameter tissue engineered vascular graft made of electrospun PCL/lecithin blend.

    Science.gov (United States)

    Zhang, Min; Wang, Kai; Wang, Zhexiang; Xing, Bin; Zhao, Qiang; Kong, Deling

    2012-11-01

    In this study, natural lecithin was incorporated into cholesterol-poly(ε-caprolactone) (Chol-PCL) by solution blending in order to modify the performance of the hydrophobic and bio-inert PCL. The fibrous Chol-PCL/lecithin membranes were fabricated by electrospinning, and the surface morphology and properties were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, and mechanical tensile testing. The blood compatibility of the scaffolds was evaluated by in vitro hemolysis assay. The cytocompatibility of the scaffolds was investigated by cell adhesion and proliferation using bone-marrow mesenchymal stem cells (MSCs). Subcutaneous implantation was also performed to evaluate the in vivo inflammatory reaction. The tubular tissue-engineered vascular graft (TEVG) was further constructed by rolling cell sheet comprising fibrous membrane and MSCs. Furthermore, endothelial cells (ECs) were seeded onto the lumen of the graft with the aim to form vascular endothelium. The preliminary results indicate that electrospun Chol-PCL/lecithin scaffolds show improved hemocompatibility and cytocompatibility compared with neat Chol-PCL, and combining the Chol-PCL/lecithin fibrous scaffold with MSCs and ECs with well controlled distribution is a promising strategy for constructing TEVGs.

  4. Passive Posterior Tibial Subluxation on Routine Knee MRI as a Secondary Sign of PCL Tear

    Directory of Open Access Journals (Sweden)

    Andrew J. Degnan

    2014-01-01

    Full Text Available The posterior drawer test is an accurate clinical test to diagnose posterior cruciate ligament (PCL, indicating laxity of the PCL that allows posterior tibial translation. This study aimed to determine whether posterior tibial translation relative to the femur on routine MRI could serve as an additional sign of PCL tear. Routine knee MRI in eleven patients (7 males, 4 females with arthroscopically confirmed isolated PCL tears were reviewed independently by two musculoskeletal radiologists. Measurements of tibial translation were made in the medial and lateral compartments of patients and controls (10 males, 12 females without clinical or MRI evidence of ligament injury. Significant medial compartment posterior tibial translation was present in patients with PCL tear compared to controls (+2.93 mm versus +0.03 mm, P=0.002 with excellent interobserver agreement (intraclass correlation coefficient (ICC = 0.94. No significant difference in lateral compartment tibial translation was observed (+0.17 mm versus −0.57 mm, P=0.366 despite excellent interobserver agreement (ICC = 0.96. Posterior tibial translation in the midmedial compartment may be a secondary sign of isolated PCL tear on routine knee MRI with passive extension without manipulation or weight bearing. Additional work in a larger cohort may better address the accuracy of this finding.

  5. Tailoring degradation of AZ31 alloy by surface pre-treatment and electrospun PCL fibrous coating

    Energy Technology Data Exchange (ETDEWEB)

    Hanas, T. [Medical Materials Laboratory, Indian Institute of Technology Madras, Chennai 600036 (India); School of Nano Science and Technology, National Institute of Technology Calicut, Calicut, Kerala 673601 (India); Sampath Kumar, T.S., E-mail: tssk@iitm.ac.in [Medical Materials Laboratory, Indian Institute of Technology Madras, Chennai 600036 (India); Perumal, Govindaraj; Doble, Mukesh [Department of Biotechnology - Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036 (India)

    2016-08-01

    AZ31 magnesium alloy was coated with polycaprolactone (PCL) nano-fibrous layer using electrospinning technique so as to control degradation in physiological environment. Before coating, the alloy was treated with HNO{sub 3} to have good adhesion between the coating and substrate. To elucidate the role of pre-treatment and coating, samples only with PCL coating as well as HNO{sub 3} treatment only were prepared for comparison. Best coating adhesion of 4B grade by ASTM D3359–09 tape test was observed for pre-treated samples. The effect of coating on in vitro degradation and biomineralization was studied using supersaturated simulated body fluid (SBF 5 ×). The weight loss and corrosion results obtained by immersion test showed that the combination of HNO{sub 3} pre-treatment and PCL coating is very effective in controlling the degradation rate and improving bioactivity. Cytotoxicity studies using L6 cells showed that PCL coated sample has better cell adhesion and proliferation compared to uncoated samples. Nano-fibrous PCL coating combined with prior acid treatment seems to be a promising method to tailor degradation rate with enhanced bioactivity of Mg alloys. - Highlights: • PCL electrospun coating on HNO{sub 3} pre-treated AZ31 alloy controls biodegradation. • Acid pre-treatment stabilizes the substrate - coating interface. • Electrospun porous coating improves biomineralization. • Coating similar to extracellular matrix enhances cell adhesion.

  6. Double Crystalline Multiblock Copolymers with Controlling Microstructure for High Shape Memory Fixity and Recovery.

    Science.gov (United States)

    Huang, Miaoming; Zheng, Liuchun; Wang, Lili; Dong, Xia; Gao, Xia; Li, Chuncheng; Wang, Dujin

    2017-09-06

    The shape memory performance of double crystalline poly(butylene succinate)-co-poly(ε-caprolactone) (PBS-co-PCL) multiblock copolymers with controlling microstructure was studied, and the corresponding microstructure origin was further quantitatively analyzed by wide and small-angle X-ray scattering (WAXS and SAXS) experiments. It was found that the multiblock copolymer with higher PCL content, proper deformation strain, and inhibited crystallization of PBS (lower crystallinity and smaller crystal size, which could be realized by quenching from the melt) would exhibit better shape memory fixity and recovery performance. WAXS and SAXS results revealed that the shape fixity ratio (Rf) was closely related with the relative crystallinity of the PCL component, while the shape recovery ratio (Rr) strongly relied on the deformation and recovery behavior of the PBS and PCL components that changed along with compositions and deformation strains. For the copolymer with higher PCL content (BS30CL70), at the lower deformation strain (0% ∼ 90%), both the PBS and PCL components after recovery had no orientation (labeled as stage I), resulting in almost complete recovery; with the deformation strain increasing (90% ∼ 200%), it was the irreversible deformation of the PCL component that largely took responsibility for the decreased Rr (stage II). On the contrary, when the PCL content decreased to 50 wt % (BS50CL50), stage I (0% ∼ 50%) and stage II (50% ∼ 100%) appeared in much lower strains; with the deformation strain increasing (100% ∼ 200%), the irreversible deformation of both PBS and PCL components was mainly responsible for the further reduction of Rr (stage III). It could exhibit excellent shape memory performance for biodegradable double crystalline multiblock copolymers by controlling the composition, deformation strain, and crystallization, which might have wide application prospects in biomedical areas.

  7. Folding control in cyclic peptides through N-methylation pattern selection: formation of antiparallel beta-sheet dimers, double reverse turns and supramolecular helices by 3alpha,gamma cyclic peptides.

    Science.gov (United States)

    Amorín, Manuel; Castedo, Luis; Granja, Juan R

    2008-01-01

    Peptide foldamers constitute a growing class of nanomaterials with potential applications in a wide variety of chemical, medical and technological fields. Here we describe the preparation and structural characteristics of a new class of cyclic peptide foldamers (3alpha,gamma-CPs) that, depending on their backbone N-methylation patterns and the medium, can either remain as flat rings that dimerize through arrays of hydrogen bonds of antiparallel beta-sheet type, or can fold into twisted double reverse turns that, in the case of double gamma-turns, associate in nonpolar solvents to form helical supramolecular structures. A 3alpha,gamma-CP consists of a number of multiples of a repeat unit made up of four amino acid residues of alternating chirality: three corresponding to alpha-amino acids and one to a gamma-amino acid (a cis-3-aminocycloalkanecarboxylic acid).

  8. Inner-shell excitation of PF 3, PCl 3, PCl 2CF 3, OPF 3 and SPF 3. Part I. Spectroscopy

    Science.gov (United States)

    Neville, John J.; Jürgensen, A.; Cavell, R. G.; Kosugi, N.; Hitchcock, A. P.

    1998-11-01

    Total ion yield spectra of PF 3, PCl 3, PCl 2CF 3, OPF 3 and SPF 3 were recorded in the region of P 2p, P 2s, S 2p, S 2s and halogen (Cl 2p, F 1s) excitation using synchrotron radiation. The P 2p spectra are interpreted with GSCF3 ab initio configuration interaction calculations optimized for core excitation studies. The experimental-theoretical comparison is based on both absolute intensities (oscillator strengths) and transition energies. The calculations indicate that several of the discrete states (e.g., that in PF 3 at 136.5 eV) are best described as LS-coupled states because the core-valence electron exchange is very large and thus the singlet-triplet splitting is larger than the spin-orbit splitting. While the state at 136.5 eV in PF 3 is particularly notable, analogous P 2p excited states with large singlet-triplet splittings are calculated in PCl 3, PCl 2CF 3, OPF 3 and SPF 3. Aspects of partial ion yield measurements (particularly the PF 3+ yield of PF 3 and the SPF 3+ yield of SPF 3) support this interpretation by revealing isolated single states without a corresponding partner at the spin-orbit splitting. The partial ion yields help clarify spectral interpretation by removing interference from overlap with adjacent states having the normal ( j, j)-coupled ion core character.

  9. A new double-foil soft x-ray array to measure T{sub e} on the MST reversed field pinch

    Energy Technology Data Exchange (ETDEWEB)

    McGarry, M. B.; Den Hartog, D. J.; Goetz, J. A. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Franz, P. [Consorzio RFX, Associazione Euratom-ENEA per la Fusione, 35127 Padova (Italy)

    2010-10-15

    A soft x-ray (SXR) diagnostic to measure electron temperature on the Madison Symmetric Torus using two complementary methods is presented. Both methods are based on the double-foil technique, which calculates electron temperature via the ratio of SXR bremsstrahlung emission from the plasma in two different energy ranges. The tomographic emissivity method applies the double-foil technique to a tomographic reconstruction of SXR emissivity, creating a two-dimensional map of temperature throughout the plasma. In contrast, the direct brightness method applies the double-foil technique directly to the measured brightness and generates vertical and horizontal radial profiles. Extensive modeling demonstrates advantages and limitations in both techniques. For example, although the emissivity technique provides a two-dimensional mapping of temperature, its reliance on multiple tomographic inversions introduces some artifacts into the results. On the other hand, the more direct brightness technique avoids these artifacts but is only able to provide a radial profile of electron temperature.

  10. Comparative Molecular Field Analysis (CoMFA for Thiotetrazole Alkynylacetanilides, a Non-Nucleoside Inhibitor of HIV-1 Double Mutant K103N/Y181C Reverse Transcriptase

    Directory of Open Access Journals (Sweden)

    Sivan Sree Kanth

    2009-01-01

    Full Text Available Non-nucleoside reverse transcriptase inhibitors (NNRTIs are allosteric inhibitors of the HIV-1 reverse transcriptase. HIV-1 resistance to nucleoside RT inhibitors such as AZT can arise through mutations in the coding region of RT. Recently a series of thioterazolyl acetanilides were reported as potent inhibitors of HIV-1 wild type and double mutant K103N/Y181C reverse transcriptase. In the present study 3D quantitative structure activity relationship (3D QSAR studies involving comparative molecular field analysis (CoFMA were performed on 28 thiotetrazole alkynylacetanilides. CoMFA was performed using sibyl software 6.7v. The molecules were divided into training set and test set. The developed model based on training set containing 20 molecules gave Q2 value of 0.587 and non cross validation R2 value of 0.961 and standard error of estimate 0.098 for CoMFA. The steric and electrostatic contributions are 42.7% and 57.3% The cross validation on test set gave R2 value of 0.74. The CoMFA model provided the most significant correlation of steric and electrostatic fields with biological activities. The information rendered by 3D QSAR model may afford valuable clues to optimize the lead and design new potential inhibitors

  11. Electrospun PCL/gelatin composite nanofiber structures for effective guided bone regeneration membranes.

    Science.gov (United States)

    Ren, Ke; Wang, Yi; Sun, Tao; Yue, Wen; Zhang, Hongyu

    2017-09-01

    Guided bone regeneration (GBR) membranes have been proved of great benefit for bone tissue engineering due to the improvement of cell attachment and proliferation. To develop GBR membranes with better biocompatibility and more proper degradation ability, here we fabricated polycaprolactone (PCL, polymer)/gelatin (protein) hybrid nanofibrous GBR membranes via electrospinning, followed by crosslinking with genipin. Acetic acid (HAc) was utilized to resolve the phase separation of PCL and gelatin, therefore homogeneous PCL/gelatin hybrid nanofibers with different ratios were successfully prepared. FTIR, XPS, TGA, DSC results proved that the proportion of PCL and gelatin in the as-spun nanofiber membranes could be simply adjusted by changing the weight ratio of PCL and gelatin in the spinning solution. SEM and AFM images demonstrated that all the nanofibers possessed uniform and smooth structures both in two dimension (2D) and three dimension (3D). The mechanical tests showed that these nanofibers exhibited appropriate tensile and strength properties, which were suitable for bone tissue engineering. CCK-8 and SEM images revealed that all the membranes were biocompatible to MC3T3-e1 cells. In addition, the in vitro osteogenesis characterizations, alizarin red in normal medium and osteogenesis medium, indicated that the nanofibers could promote bone formation. Therefore, all these results could suggest that our design of electrospun polymer/protein nanofiber membranes was effective for guided bone regeneration. Copyright © 2017. Published by Elsevier B.V.

  12. Active Bilayer PE/PCL Films for Food Packaging Modified with Zinc Oxide and Casein

    Directory of Open Access Journals (Sweden)

    Ana Rešček

    2015-12-01

    Full Text Available This paper studies the properties of active polymer food packaging bilayer polyethylene/polycaprolactone (PE/PCL films. Such packaging material consists of primary PE layer coated with thin film of PCL coating modified with active component (zinc oxide or zinc oxide/casein complex with intention to extend the shelf life of food and to maintain the quality and health safety. The influence of additives as active components on barrier, mechanical, thermal and antimicrobial properties of such materials was studied. The results show that, in comparison to the neat PE and PE/PCL films, some of PE/PCL bilayer films with additives exhibit improved barrier properties i.e. decreased water vapour permeability. Higher thermal stability of modified PE/PCL material is obtained due to a modified mechanism of thermal degradation. The samples with the additive nanoparticles homogeneously dispersed in the polymer matrix showed good mechanical properties. Addition of higher ZnO content contributes to the enhanced antibacterial activity of a material.

  13. Pcl/Chitosan Blended Nanofibrous Tubes Made by Dual Syringe Electrospinning

    Directory of Open Access Journals (Sweden)

    Hild Martin

    2015-03-01

    Full Text Available 3D tubular scaffolds made from Poly-(Ɛ-caprolactone (PCL/chitosan (CS nanofibres are very promising candidate as vascular grafts in the field of tissue engineering. In this work, the fabrication of PCL/CS-blended nanofibrous tubes with small diameters by electrospinning from separate PCL and CS solutions is studied. The influence of different CS solutions (CS/polyethylene glycol (PEO/glacial acetic acid (AcOH, CS/trifluoroacetic acid (TFA, CS/ AcOH on fibre formation and producibility of nanofibrous tubes is investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR is used to verify the presence of CS in the blended samples. Tensile testing and pore size measurements are done to underline the good prerequisites of the fabricated blended PCL/ CS nanofibrous tubes as potential scaffolds for vascular grafts. Tubes fabricated from the combination of PCL and CS dissolved in AcOH possesses properties, which are favourable for future cell culture studies.

  14. Hydrophilic block azidation of PCL-b-PEO block copolymers from epichlorohydrin.

    Science.gov (United States)

    Liu, Junjie; Gan, Zhihua

    2014-05-01

    Amphiphilic diblock copolymers poly(ϵ-caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) with well-controlled pendant azido groups along the hydrophilic PEO block, that is, poly(ϵ-caprolactone)-b-poly(ethylene oxide-co-glycidyl azide) (PCL-b-P(EO-co-GA)), are synthesized from poly(ϵ-caprolactone)-b-poly(ethylene oxide-co-epichlorohydrin) (PCL-b-P(EO-co-ECH)). The further conversion of those azido groups along the hydrophilic block of copolymers into amino or carboxyl groups via click chemistry is studied. The micelles self-assembled from PCL-b-P(EO-co-GA) with azido groups on the shell are crosslinked by the dialkynyl-PEO. The micelles with crosslinked shell show better stability, higher drug loading capacities, subsequent faster drug release rate, and higher cytotoxicity to cancer cells. The introduction of azido groups into PCL-b-PEO amphiphilic diblock copolymers from epichlorohydrin in PEO hydrophilic block in this work provides a new method for biofunctionalization of micelles via mild click chemistry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. An additive manufacturing-based PCL-alginate-chondrocyte bioprinted scaffold for cartilage tissue engineering.

    Science.gov (United States)

    Kundu, Joydip; Shim, Jin-Hyung; Jang, Jinah; Kim, Sung-Won; Cho, Dong-Woo

    2015-11-01

    Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self-assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three-dimensional (3D) cell-printed scaffolds using layer-by-layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell-encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell-based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL-alginate gel constructs. PCL-alginate gels containing transforming growth factor-β (TGFβ) showed higher ECM formation. The 3D cell-printed scaffolds of PCL-alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL-alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell-printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. Copyright © 2013 John Wiley & Sons, Ltd.

  16. In vitro degradation of poly (L-co-D,L lactic acid containing PCL-T

    Directory of Open Access Journals (Sweden)

    Marcia Adriana Tomaz Duarte

    2014-01-01

    Full Text Available The application of polymer-based bioresorbable temporary devices in the medical field grows continuously, and professionals from several areas act to solve problems related to body functions lost due to diseases, accidents or natural wear. Here we study the influence from poly(caprolactonetriol (PCL-T on the degeneration process in the copolymer poly(L-co-DL-lactic acid (PLDLA membrane, by producing PLDLA/PCL-T blends with 90/10, 70/30 and 50/50 relative concentrations. The data for in vitro degradation showed that PCL-T decreases the rate of PLDLA. This was obtained with the following techniques: Differential Scanning Calorimetry (DSC, Thermogravimetric Analysis (TGA, Gel Permeation Chromatography (GPC and Scanning Electron Microscopy (SEM. Therefore, it is possible to vary the membrane degradation rate by changing the blend composition, which is a tool to tailor a biomaterial.

  17. PEG-PCL-based nanomedicines: A biodegradable drug delivery system and its application.

    Science.gov (United States)

    Grossen, Philip; Witzigmann, Dominik; Sieber, Sandro; Huwyler, Jörg

    2017-08-28

    The lack of efficient therapeutic options for many severe disorders including cancer spurs demand for improved drug delivery technologies. Nanoscale drug delivery systems based on poly(ethylene glycol)-poly(ε-caprolactone) copolymers (PEG-PCL) represent a strategy to implement therapies with enhanced drug accumulation at the site of action and decreased off-target effects. In this review, we discuss state-of-the-art nanomedicines based on PEG-PCL that have been investigated in a preclinical setting. We summarize the various synthesis routes and different preparation methods used for the production of PEG-PCL nanoparticles. Additionally, we review physico-chemical properties including biodegradability, biocompatibility, and drug loading. Finally, we highlight recent therapeutic applications investigated in vitro and in vivo using advanced systems such as triggered release, multi-component therapies, theranostics, or gene delivery systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Electrospun PLA: PCL composites embedded with unmodified and 3-aminopropyltriethoxysilane (ASP) modified halloysite nanotubes (HNT)

    Science.gov (United States)

    Haroosh, Hazim J.; Dong, Yu; Chaudhary, Deeptangshu S.; Ingram, Gordon D.; Yusa, Shin-ichi

    2013-02-01

    Electrospinning is a simple and versatile fiber synthesis technique in which a high-voltage electric field is applied to a stream of polymer melt or polymer solution, resulting in the formation of continuous micro/nanofibers. Halloysite nanotubes (HNT) have been found to achieve improved structural and mechanical properties when embedded into various polymer matrices. This research work focuses on blending poly( ɛ-caprolactone) (PCL) (9 and 15 wt%/v) and poly(lactic acid) (PLA) (fixed at 8 wt%/v) solutions with HNT at two different concentrations 1 and 2 wt%/v. Both unmodified HNT and HNT modified with 3-aminopropyltriethoxysilane (ASP) were utilized in this study. Fiber properties have been shown to be strongly related to the solution viscosity and electrical conductivity. The addition of HNT increased the solution viscosity, thus resulting in the production of uniform fibers. For both PCL concentrations, the average fiber diameter increased with the increasing of HNT concentration. The average fiber diameters with HNT-ASP were reduced considerably in comparison to those with unmodified HNT when using 15 wt%/v PCL. Slightly better dispersion was obtained for PLA: PCL composites embedded with HNT-ASP compared to unmodified HNT. Furthermore, the addition of HNT-ASP to the polymeric blends resulted in a moderate decrease in the degree of crystallinity, as well as slight reductions of glass transition temperature of PCL, the crystallization temperature and melting temperature of PLA within composite materials. The infrared spectra of composites confirmed the successful embedding of HNT-ASP into PLA: PCL nanofibers relative to unmodified HNT due to the premodification using ASP to reduce the agglomeration behavior. This study provides a new material system that could be potentially used in drug delivery, and may facilitate good control of the drug release process.

  19. Determining the mechanical properties of electrospun poly-ε-caprolactone (PCL) nanofibers using AFM and a novel fiber anchoring technique

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Stephen R.; Banerjee, Soham; Bonin, Keith; Guthold, Martin, E-mail: gutholdm@wfu.edu

    2016-02-01

    Due to its low cost, biocompatibility and slow bioresorption, poly-ε-caprolactone (PCL) continues to be a suitable material for select biomedical engineering applications. We used a combined atomic force microscopy (AFM)/optical microscopy technique to determine key mechanical properties of individual electrospun PCL nanofibers with diameters between 440–1040 nm. Compared to protein nanofibers, PCL nanofibers showed much lower adhesion, as they slipped on the substrate when mechanically manipulated. We, therefore, first developed a novel technique to anchor individual PCL nanofibers to micrometer-sized ridges on a substrate, and then mechanically tested anchored nanofibers. When held at constant strain, tensile stress relaxed with fast and slow relaxation times of 1.0 ± 0.3 s and 8.8 ± 3.1 s, respectively. The total tensile modulus was 62 ± 26 MPa, the elastic (non-relaxing) component of the tensile modulus was 53 ± 36 MPa. Individual PCL fibers could be stretched elastically (without permanent deformation) to strains of 19–23%. PCL nanofibers are rather extensible; they could be stretched to a strain of at least 98%, and a tensile strength of at least 12 MPa, before they slipped off the AFM tip. PCL nanofibers that had aged for over a month at ambient conditions became stiffer and less elastic. Our technique provides accurate nanofiber mechanical data, which are needed to guide construction of scaffolds for cells and other biomedical devices. - Highlights: • Developed technique to anchor single nanofibers on microridges • Determined mechanical properties of e-spun PCL fibers • E-spun PCL fibers have similar mechanical properties as wet fibrin fibers. • E-spun PCL fiber total elastic modulus is ~ 60 MPa. • E-spun PCL fiber extensibility is > 100%.

  20. CONFIABILIDAD Y VALIDEZ DE LA VERSIÓN CHILENA DE LA HARE PCL-R Chilean version of Hare PCL-R: a study of reliability and validity

    Directory of Open Access Journals (Sweden)

    Elizabeth León-Mayer

    2010-01-01

    Full Text Available Antecedentes. En Chile, al igual que en otros países latinoamericanos, diversas modificaciones judiciales y el interés de los profesionales en sistematizar sus métodos de evaluación en psicopatía promovieron la traducción, adaptación y revisión de las propiedades psicométricas de la Hare Psychopathy Checklist Revised (PCL-R. Objetivo. Evaluar aspectos de la confiabilidad y validez de la versión chilena del PCL-R en población forense masculina chilena. Material y métodos. Se realizó traducción y retrotraducción de la escala con la autorización del autor y editorial; se constituyó una muestra de 293 sujetos varones penados que aceptaron participar en la investigación. Entre otros análisis, se contrastó el diagnóstico obtenido a ciegas con la PCL-R con el aportado por el equipo técnico de Gendarmería de Chile. Resultados. La congruencia interna medida con Alfa de Cronbach fue la siguiente: total =0,91; F1= 0,86; F2 = 0,87; F3 = 0,67; F4= 0,77. Valor Kappa ambos tipos de evaluaciones = 0,804; p Background. In Chile as in other Latin American countries the introduction of the Adversarial Model in the Judicial System increased the need for the systematization of the evaluation of psychopathy, thus making necessary the translation, adaptation and revision of the psychometric properties of the Hare Psychopathy Checklist Revised. Objective. To evaluate aspects of the reliability and validity of the Chilean version of the PCL-R in Chilean male inmate population. Materials and methods. The PCL-R was translated and backtranslated with the authorization of the author and of the Editorial House. A sample of 293 inmates was constituted and the respective informed consent obtained. Several analyses were made including a blind comparison of the diagnosis made with the PCL-R and the one made by the Technical Area of Gendarmería of Chile. Results. The internal congruence measured with Crombach Alfa was: total =0,91; F1= 0,86; F2 = 0,87; F3

  1. Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Surucu, Seda [Department of Metallurgical and Materials Engineering, Atilim University, Incek, Golbasi, 06836, Ankara (Turkey); Masur, Kai [Leibniz Institute for Plasma Science and Technology (Germany); Turkoglu Sasmazel, Hilal, E-mail: hilal.sasmazel@atilim.edu.tr [Department of Metallurgical and Materials Engineering, Atilim University, Incek, Golbasi, 06836, Ankara (Turkey); Von Woedtke, Thomas; Weltmann, Klaus Dieter [Leibniz Institute for Plasma Science and Technology (Germany)

    2016-11-01

    Highlights: • Electrospun PCL/chitosan/PCL scaffolds introduced to the literature by us were modified with atmospheric pressure plasma jets. • Plasma was fed into the system with different gas flow rates, time and distances. • Topographical and functional changes were examined by various characterization methods. • Optimum plasma treatment parameters for enhanced topography and functionality were determined. • Electrospun hybrid plasma surface modified samples showed the increased biocompatibility performance of L929 fibroblast cells. - Abstract: This paper reports Ar gas, Ar + O{sub 2}, Ar + O{sub 2} + N{sub 2} gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O{sub 2} + N{sub 2} gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O{sub 2} + N{sub 2} gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on

  2. On the Viability of PTSD Checklist (PCL) Short Form Use: Analyses from Mississippi Gulf Coast Hurricane Katrina Survivors

    Science.gov (United States)

    Hirschel, Michael J.; Schulenberg, Stefan E.

    2010-01-01

    One measure commonly used to assess posttraumatic stress disorder is the PTSD Checklist (PCL). Lang and Stein (2005) extracted 4 subsets of PCL items, validating 2 of them for possible use in screening in primary care settings. The viability of the 4 item subsets was evaluated psychometrically in the present study with a sample of Hurricane…

  3. A reversible fluorescent probe based on C[double bond, length as m-dash]N isomerization for the selective detection of formaldehyde in living cells and in vivo.

    Science.gov (United States)

    Song, Xinyu; Han, Xiaoyue; Yu, Fabiao; Zhang, Jinjin; Chen, Lingxin; Lv, Changjun

    2018-01-15

    Formaldehyde (FA) is an endogenously produced reactive carbonyl species (RCS) through biological metabolic processes whose concentration is closely related to human health and disease. Noninvasive and real-time detection of FA concentration in organisms is very important for revealing the physiological and pathological functions of FA. Herein, we design and synthesize a reversible fluorescent probe BOD-NH2 for the detection of FA in living cells and in vivo. The probe is composed of two moieties: the BODIPY fluorophore and the primary amino group response unit. The probe undergoes an intracellular aldimine condensation reaction with FA and forms imine (C[double bond, length as m-dash]N) which will result in C[double bond, length as m-dash]N isomerization and rotation to turn-off the fluorescence of the probe. It is important that the probe can show a reversible response to FA. The probe BOD-NH2 has been successfully applied for detecting and imaging FA in the cytoplasm of living cells. BOD-NH2 is capable of detecting fluctuations in the levels of endogenous and exogenous FA in different types of living cells. The probe can be used to visualize the FA concentration in fresh hippocampus and the probe can further qualitatively evaluate the FA concentrations in ex vivo-dissected organs. Moreover, BOD-NH2 can also be used for imaging in mice. The above applications make our new probe a potential chemical tool for the study of physiological and pathological functions of FA in cells and in vivo.

  4. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  5. Improved Safety for Molecular Diagnosis of Classical Rabies Viruses by Use of a TaqMan Real-Time Reverse Transcription-PCR "Double Check" Strategy

    DEFF Research Database (Denmark)

    Hoffmann, B.; Freuling, C. M.; Wakeley, P. R.

    2010-01-01

    To improve the diagnosis of classical rabies virus with molecular methods, a validated, ready-to-use, real-time reverse transcription-PCR (RT-PCR) assay was developed. In a first step, primers and 6-carboxyfluorescien-labeled TaqMan probes specific for rabies virus were selected from the consensus...... sequence of the nucleoprotein gene of 203 different rabies virus sequences derived from GenBank. The selected primer-probe combination was highly specific and sensitive. During validation using a sample set of rabies virus strains from the virus archives of the Friedrich-Loeffler-Institut (FLI; Germany......), the Veterinary Laboratories Agency (VLA; United Kingdom), and the DTU National Veterinary Institute (Lindholm, Denmark), covering the global diversity of rabies virus lineages, it was shown that both the newly developed assay and a previously described one had some detection failures. This was overcome...

  6. In vitro evaluation of the effects of electrospun PCL nanofiber mats containing the microalgae Spirulina (Arthrospira) extract on primary astrocytes.

    Science.gov (United States)

    Kim, Sung Hoon; Shin, Chungwhan; Min, Seul Ki; Jung, Sang-Myung; Shin, Hwa Sung

    2012-02-01

    The blue-green microalgae, Spirulina, a harmless food and pharmaceutical additive, has several bioactive compounds that have therapeutic functions. Polycaprolactone (PCL) is a biocompatible and biodegradable polymer that has widely been used for tissue engineering. The electrospun PCL nanofiber containing Spirulina (PCL-Spirulina) was fabricated and tested as a potential extracellular matrix material for a culture of primary astrocytes, which play important roles in CNS injured systems. Spirulina extract was observed to increase growth and metabolic activity of rat primary astrocytes without any harm once added to the culture media. However, PCL-Spirulina nanofiber was proven to alleviate astrocyte activity. Through this research and to the best of our knowledge, we first suggest a novel composite nanomaterial, an electrospun PCL-Spirulina nanofiber that could be used to treat CNS injured systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Osteogenic activity of cyclodextrin-encapsulated doxycycline in a calcium phosphate PCL and PLGA composite

    Energy Technology Data Exchange (ETDEWEB)

    Trajano, V.C.C.; Costa, K.J.R. [Restorative Dentistry Department, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Lanza, C.R.M. [Department of Oral Clinical, Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Sinisterra, R.D. [Chemistry Department, ICEX, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Cortés, M.E., E-mail: mecortes@ufmg.br [Restorative Dentistry Department, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2016-07-01

    Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in β-cyclodextrin (βCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/βCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1 day, 7 day, and 14 days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7 days and 14 days, and mineral nodule formation after 14 days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25 μg/mL DOX/βCD had increased cell proliferation (p < 0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. AP activity and collagen secretion levels were also elevated in osteoblasts exposed to the DOX/βCD composite (p < 0.05 vs. controls) and reached a maximum after 14 days. These results were corroborated by Von Kossa test results, which showed strong formation of mineralization nodules during the same time period. SEM of the composite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/βCD-containing BCP ceramic composite. - Highlights: • Doxycycline encapsulated in β-cyclodextrin was incorpored into a polycaprolactone - poly(lactic-co-glycolic acid) - calcium phosphate • Composite’s scaffold carrying doxycycline

  8. Pyrrolo-dC Metal-Mediated Base Pairs in the Reverse Watson-Crick Double Helix: Enhanced Stability of Parallel DNA and Impact of 6-Pyridinyl Residues on Fluorescence and Silver-Ion Binding.

    Science.gov (United States)

    Yang, Haozhe; Mei, Hui; Seela, Frank

    2015-07-06

    Reverse Watson-Crick DNA with parallel-strand orientation (ps DNA) has been constructed. Pyrrolo-dC (PyrdC) nucleosides with phenyl and pyridinyl residues linked to the 6 position of the pyrrolo[2,3-d]pyrimidine base have been incorporated in 12- and 25-mer oligonucleotide duplexes and utilized as silver-ion binding sites. Thermal-stability studies on the parallel DNA strands demonstrated extremely strong silver-ion binding and strongly enhanced duplex stability. Stoichiometric UV and fluorescence titration experiments verified that a single (2py) PyrdC-(2py) PyrdC pair captures two silver ions in ps DNA. A structure for the PyrdC silver-ion base pair that aligns 7-deazapurine bases head-to-tail instead of head-to-head, as suggested for canonical DNA, is proposed. The silver DNA double helix represents the first example of a ps DNA structure built up of bidentate and tridentate reverse Watson-Crick base pairs stabilized by a dinuclear silver-mediated PyrdC pair. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Amphiphilic core-shell nanocarriers based on hyperbranched poly(ester amide)-star-PCL: synthesis, characterization, and potential as efficient phase transfer agent.

    Science.gov (United States)

    Lin, Ying; Liu, Xiaohui; Dong, Zhongmin; Li, Baixiang; Chen, Xuesi; Li, Yue-Sheng

    2008-10-01

    Amphiphilic biodegradable star-shaped polymer was conveniently prepared by the Sn(Oct)2-catalyzed ring opening polymerization of epsilon-caprolactone (CL) with hyperbranched poly(ester amide) (PEA) as a macroinitiator. Various monomer/initiator ratios were employed to vary the length of the PCL arms. (1)H NMR and FTIR characterizations showed the successful synthesis of star polymer with high initiation efficiency. SEC analysis using triple detectors, RI, light scattering, and viscosity confirmed the controlled manner of polymerization and the star architecture. Because of the hydrophilic PEA core and hydrophobic PCL shell, the obtained star polymers displayed inverted unimolecular micellar structure confirmed by dynamic light scattering. Three water soluble dyes, congo red, methyl orange, and bromophenol blue, were used to investigate the host-guest behavior of the micelles. It proved that the core-shell unimolecular reverse micelles were able to transport polar dyes from water to the organic phase with a high efficiency of up to 22.6 dyes per polymer, indicating a great potential of the micelles as drug carriers. The influence of arm length and core size on the load efficiency of the nanocarrier was also evaluated.

  10. Chronic caffeine treatment reverses memory impairment and the expression of brain BNDF and TrkB in the PS1/APP double transgenic mouse model of Alzheimer’s disease

    Science.gov (United States)

    HAN, KUN; JIA, NING; LI, JI; YANG, LI; MIN, LIAN-QIU

    2013-01-01

    The objective of this study was to investigate the effects of varying doses of caffeine on memory impairment and the expression of brain neurotrophic derived factor (BNDF) and TrkB in PS1/APP double transgenic mouse models. PS1/APP double transgenic mice were administered 0.3 ml/day of saline, 1.5 mg/day of caffeine or 0.75 mg/day of caffeine for eight weeks. A water maze test and western blotting were used to determine the memory capability and expression of hippocampal BNDF and TrkB of the mice. The results demonstrated that 0.75 mg/day and 1.5 mg/day doses of caffeine significantly increased memory capability and the expression of hippocampal BDNF and TrkB in PS1/APP mice with a dose-response effect. The results suggested that chronic caffeine treatment may reverse memory impairment in PS1/APP transgenic mice, and BDNF and its receptor TrkB, may be involved in this process. PMID:23900282

  11. Fabrication and characterization of PCL/gelatin composite nanofibrous scaffold for tissue engineering applications by electrospinning method

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Sneh [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India); Dinda, Amit Kumar [Department of Pathology, All India Institute of Medical Science, New Delhi, 110029 (India); Mishra, Narayan Chandra, E-mail: mishrawise@googlemail.com [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India)

    2013-04-01

    In the present study, composite nanofibrous tissue engineering-scaffold consisting of polycaprolactone and gelatin, was fabricated by electrospinning method, using a new cost-effective solvent mixture: chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin. The morphology of the nanofibrous scaffold was investigated by using field emission scanning electron microscopy (FE-SEM) which clearly indicates that the morphology of nanofibers was influenced by the weight ratio of PCL to gelatin in the solution. Uniform fibers were produced only when the weight ratio of PCL/gelatin is sufficiently high (10:1). The scaffold was further characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, and X-ray diffraction (XRD). FT-IR and TG analysis indicated some interactions between PCL and gelatin molecules within the scaffold, while XRD results demonstrated crystalline nature of PCL/gelatin composite scaffold. Cytotoxicity effect of scaffold on L929 mouse fibroblast cells was evaluated by MTT assay and cell proliferation on the scaffold was confirmed by DNA quantification. Positive results of MTT assay and DNA quantification L929 mouse fibroblast cells indicated that the scaffold made from the combination of natural polymer (gelatin) and synthetic polymer (PCL) may serve as a good candidate for tissue engineering applications. - Highlights: ► PCL/Gelatin scaffold was successfully fabricated by electrospinning method. ► PCL in CHCl{sub 3}/CH{sub 3}OH and gelatin in acetic acid: a novel polymer-solvent system. ► The morphology of nanofibers was influenced by the weight ratio of PCL/gelatin. ► Chemical interactions between PCL and gelatin molecules enhanced cell growth. ► Cell culture studies indicate the suitability of scaffold for tissue regeneration.

  12. Enhanced guided bone regeneration by asymmetrically porous PCL/pluronic F127 membrane and ultrasound stimulation.

    Science.gov (United States)

    Oh, Se Heang; Kim, Tae Ho; Chun, So Young; Park, Eui Kyun; Lee, Jin Ho

    2012-01-01

    Recently, we developed a novel method for fabricating a guided bone regeneration (GBR) membrane with an asymmetrical pore structure and hydrophilicity by an immersion precipitation method. Results from an animal study, in a cranial defect model in rats, indicated that the unique asymmetrically porous GBR membrane would provide a good environment for bone regeneration. In the present study, we applied low intensity pulsed ultrasound as a simple and non-invasive stimulus to an asymmetrically porous polycaprolactone (PCL)/Pluronic F127 GBR membrane-implanted site transcutaneously in rats to investigate the feasibility of using ultrasound to stimulate enhanced bone regeneration through the membrane. It was observed that the ultrasound-stimulated PCL/F127 GBR membrane group had much faster bone regeneration behavior than a PCL/F127 membrane group w/o ultrasound or a control group (w/o membrane and ultrasound). The greater bone regeneration behavior in the GBR membrane/ultrasound group may be caused by a synergistic effect of the asymmetrically porous PCL/F127 membrane with unique properties (selective permeability, hydrophilicity and osteoconductivity), and the stimulatory effect of ultrasound (induction of angiogenesis and osteogenesis of cells).

  13. Development of an electrospun nano-apatite/PCL composite membrane for GTR/GBR application.

    Science.gov (United States)

    Yang, Fang; Both, Sanne K; Yang, Xuechao; Walboomers, X Frank; Jansen, John A

    2009-11-01

    In dental practice, membranes are used as a barrier to prevent soft tissue ingrowth and create space for slowly regenerating periodontal and bony tissues. The aim of this study was to develop a biodegradable membrane system which can be used for guided tissue or bone regeneration. Three types of composite fibrous membranes based on nano-apatite (nAp) and poly(epsilon-caprolactone) (PCL) were made by electrospinning, i.e. n0 (nAp:PCL=0:100), n25 (nAp:PCL=25:100) and n50 (nAp:PCL=50:100) with average fiber diameters ranging from 320 to 430 nm. Their structural, mechanical, chemical and biological properties were evaluated. Tensile test revealed that n25 had the highest strength and toughness, indicating there is an optimal ratio of nAp to polymer for mechanical reinforcement. Subsequently, a simulated body fluid immersion test confirmed that the presence of nAp enhanced the bioactive behavior of the membranes. Finally, an in vitro osteoblast cell study showed that all membranes supported proliferation, but the presence of nAp facilitated an early cell differentiation. This study demonstrated that an electrospun membrane incorporating nAp is strong, enhances bioactivity and supports osteoblast-like cell proliferation and differentiation. The membrane system can be used as a prototype for the further development of an optimal membrane for clinical use.

  14. Fabrication and Characterization of Electrospun PCL-MgO-Keratin-Based Composite Nanofibers for Biomedical Applications

    Science.gov (United States)

    Boakye, Maame A. D.; Rijal, Nava P.; Adhikari, Udhab; Bhattarai, Narayan

    2015-01-01

    Polymeric nanofibers are of great interest in biomedical applications, such as tissue engineering, drug delivery and wound healing, due to their ability to mimic and restore the function of natural extracellular matrix (ECM) found in tissues. Electrospinning has been heavily used to fabricate nanofibers because of its reliability and effectiveness. In our research, we fabricated poly(ε-caprolactone)-(PCL), magnesium oxide-(MgO) and keratin (K)-based composite nanofibers by electrospinning a blend solution of PCL, MgO and/or K. The electrospun nanofibers were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mechanical tensile testing and inductively-coupled plasma optical emission spectroscopy (ICP-OES). Nanofibers with diameters in the range of 0.2–2.2 µm were produced by using different ratios of PCL/MgO and PCL-K/MgO. These fibers showed a uniform morphology with suitable mechanical properties; ultimate tensile strength up to 3 MPa and Young’s modulus 10 MPa. The structural integrity of nanofiber mats was retained in aqueous and phosphate buffer saline (PBS) medium. This study provides a new composite material with structural and material properties suitable for potential application in tissue engineering. PMID:28793426

  15. Biotreatment effects in films and blends of PVC/PCL previously treated with heat

    Directory of Open Access Journals (Sweden)

    Adriana de Campos

    2005-03-01

    Full Text Available Studies were carried out on biomodification and the pre-heat (130(0C influence on Poly (vinyl chloride / Poly (epsilon-caprolactone films. The results showed that heat pre-treatment improved the biomodification of PVC films, but it inhibited the biomodification of the PVC/PCL film.Poli épsilon-caprolactona é um importante polímero biodegradável e miscível com o PVC, um polímero sintético industrial, termo susceptível e não biodegradável. A blenda PVC/PCL é importante quanto a suas propriedades mecânicas e biodegradabilidade. Neste trabalho foi analisada a biomodificação da blenda PVC/PCL pré-tratada com calor (130ºC, através da espectroscopia UV-Vis. Os resultados mostraram que o pré-tratamento com calor pode facilitar a biomodificação em filmes de PVC, mas pode inibir a biomodificação nos filmes da blenda PVC/PCL.

  16. Enhanced Vascularization in Hybrid PCL/Gelatin Fibrous Scaffolds with Sustained Release of VEGF

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2015-01-01

    Full Text Available Creating a long-lasting and functional vasculature represents one of the most fundamental challenges in tissue engineering. VEGF has been widely accepted as a potent angiogenic factor involved in the early stages of blood vessel formation. In this study, fibrous scaffolds that consist of PCL and gelatin fibers were fabricated. The gelatin fibers were further functionalized by heparin immobilization, which provides binding sites for VEGF and thus enables the sustained release of VEGF. In vitro release test confirms the sustained releasing profile of VEGF, and stable release was observed over a time period of 25 days. In vitro cell assay indicates that VEGF release significantly promoted the proliferation of endothelial cells. More importantly, in vivo subcutaneous implantation reflects that vascularization has been effectively enhanced in the PCL/gelatin scaffolds compared with the PCL counterpart due to the sustained release of VEGF. Therefore, the heparinized PCL/gelatin scaffolds developed in this study may be a promising candidate for regeneration of complex tissues with sufficient vascularization.

  17. The performance of dental pulp stem cells on nanofibrous PCL/gelatin/nHA scaffolds.

    NARCIS (Netherlands)

    Yang, X.; Yang, F.; Walboomers, X.F.; Bian, Z.; Fan, M.; Jansen, J.A.

    2010-01-01

    The aim of current study is to investigate the in vitro and in vivo behavior of dental pulp stem cells (DPSCs) seeded on electrospun poly(epsilon-caprolactone) (PCL)/gelatin scaffolds with or without the addition of nano-hydroxyapatite (nHA). For the in vitro evaluation, DNA content, alkaline

  18. Engineered electrospun polycaprolactone (PCL)/octacalcium phosphate (OCP) scaffold for bone tissue engineering.

    Science.gov (United States)

    Heydari, Zohre; Mohebbi-Kalhori, Davod; Afarani, Mahdi Shafiee

    2017-12-01

    The main challenge in bone tissue engineering is to find suitable biological substitutes which act as scaffolds. Hence, in this work, a novel scaffold composed of octacalcium phosphate (OCP) particles fabricated by co-precipitation method and polycaprolactone (PCL) using electrospinning technique was introduced. The electrospun scaffolds were characterized by SEM, FTIR, XRD, DSC and TGA analysis. The mechanical properties of the composite scaffolds including maximum tensile stress, strain at break and Young modulus were measured. The bioactivity of the scaffolds was determined by soaking in simulated body fluid (SBF). The osteoblast human G-292 cells were seeded on the scaffold's surface for in vitro studies including cell culture and MTT assay. The FTIR and XRD results showed that OCP component has an appropriate incorporation into the polymeric PCL matrix. The SEM analysis exhibited a significant reduction in the fiber size thanks to the OCP. The results of tensile test confirmed that the PCL/OCP composite introduced suitable mechanical properties. Furthermore, the OCP particles led to form hydroxyapatite layer on the scaffold's surface in the vicinity of SBF solution. The obtained results from the MTT assay described that OCP particles have a positive impact on the growth of the osteoblast human G-292 cells on the scaffolds. Overall, aforesaid features of the PCL/OCP composite scaffold make it a great candidate for the bone tissue engineering application. Copyright © 2017. Published by Elsevier B.V.

  19. Fabrication and Characterization of Electrospun PCL-MgO-Keratin-Based Composite Nanofibers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Maame A. D. Boakye

    2015-07-01

    Full Text Available Polymeric nanofibers are of great interest in biomedical applications, such as tissue engineering, drug delivery and wound healing, due to their ability to mimic and restore the function of natural extracellular matrix (ECM found in tissues. Electrospinning has been heavily used to fabricate nanofibers because of its reliability and effectiveness. In our research, we fabricated poly(ε-caprolactone-(PCL, magnesium oxide-(MgO and keratin (K-based composite nanofibers by electrospinning a blend solution of PCL, MgO and/or K. The electrospun nanofibers were analyzed by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, mechanical tensile testing and inductively-coupled plasma optical emission spectroscopy (ICP-OES. Nanofibers with diameters in the range of 0.2–2.2 µm were produced by using different ratios of PCL/MgO and PCL-K/MgO. These fibers showed a uniform morphology with suitable mechanical properties; ultimate tensile strength up to 3 MPa and Young’s modulus 10 MPa. The structural integrity of nanofiber mats was retained in aqueous and phosphate buffer saline (PBS medium. This study provides a new composite material with structural and material properties suitable for potential application in tissue engineering.

  20. Ultraporous interweaving electrospun microfibers from PCL-PEO binary blends and their cellular response

    DEFF Research Database (Denmark)

    Chen, Menglin; Li, Yanfang; Besenbacher, Flemming

    2015-01-01

    from a blend of polycaprolactone (PCL) and polyethylene oxide (PEO) in a DCM-DMF mixed solution when the ratio between each component reached a threshold and when the electrospinning parameters were delicately controlled. We further investigated their influence on cell infiltration and colonization...

  1. Facile fabrication of aloe vera containing PCL nanofibers for barrier membrane application.

    Science.gov (United States)

    Carter, Princeton; Rahman, Shekh M; Bhattarai, Narayan

    2016-01-01

    Guided tissue regeneration (GTR) is a widely used method in dental surgical procedures that utilizes a barrier membrane to exclude migration of epithelium and ensure repopulation of periodontal ligament cells at the sites having insufficient gingiva. Commercial GTR membranes are typically composed of synthetic polymers that have had mild clinical success mostly because of their lack of proper bioactivity and appropriate degradation profile. In this study, a natural polymer, aloe vera was blended with polycaprolactone (PCL) to create nanofibrous GTR membranes by electrospinning. Aloe vera has proven anti-inflammatory properties and enhances the regeneration of periodontium tissues. PCL, a synthetic polymer, is well known to produce miscible polyblends nanofibers with natural polymers. Nanofibrous membranes with varying composition of PCL to aloe vera were fabricated, and several physicochemical and biological properties, such as fiber morphology, wettability, chemical structure, mechanical strength, and cellular compatibility of the membranes were analyzed. PCL/aloe vera membranes with ratios from 100/00 to 70/30 showed good uniformity in fiber morphology and suitable mechanical properties, and retained the integrity of their fibrous structure in aqueous solutions. Experimental results, using cell viability assay and cell attachment observation, showed that the nanofibrous membranes support 3T3 cell viability and could be a potential candidate for GTR therapy.

  2. Regulation of the biosynthesis of cyclic lipopeptides from Pseudomonas putida PCL1445

    NARCIS (Netherlands)

    Dubern, Jean-Frédéric

    2006-01-01

    Pseudomonas putida strain PCL1445 produces two cyclic lipopeptides, named putisolvins I and II, which represent a Novel class of biosurfactants. Putisolvins reduce the surface tension between liquid and air, and disrupt already existing biofilms of several Pseudomonas sp., including those of the

  3. Technical note: easy graft passage without posterior portals in PCL reconstruction.

    NARCIS (Netherlands)

    Broek, C.M. van den; Tienen, T.G. van; Defoort, K.C.; Wymenga, A.B.

    2012-01-01

    Graft passage during arthroscopically assisted, single-bundle transtibial PCL reconstruction is a technically demanding surgical procedure. We propose the use of a so called Deschamps clamp, originally designed for cerclage wire transport, in combination with a meniscal repair needle with an eye.

  4. The Fabrication and Characterization of PCL/Rice Husk Derived Bioactive Glass-Ceramic Composite Scaffolds

    Directory of Open Access Journals (Sweden)

    Farnaz Naghizadeh

    2014-01-01

    Full Text Available The present study was conducted to fabricate a 3D scaffold using polycaprolactone (PCL and silicate based bioactive glass-ceramic (R-SBgC. Different concentrations of R-SBgC prepared from rice husk ash (RHA were combined with PCL to fabricate a composite scaffold using thermally induced phase separation (TIPS method. The products were then characterized using SEM and EDX. The results demonstrated that R-SBgC in PCL matrix produced a bioactive material which has highly porous structure with interconnected porosities. There appears to be a relationship between the increase in R-SBgC concentration and increased material density and compressive modulus; however, increasing R-SBgC concentration result in reduced scaffold porosity. In conclusion, it is possible to fabricate a PCL/bioactive glass-ceramic composite from processed rice husk. Varying the R-SBgC concentrations can control the properties of this material, which is useful in the development of the ideal scaffold intended for use as a bone substitute in nonload bearing sites.

  5. Design of biodegradable PCL/PI films as a joining tape for grafting plant.

    Science.gov (United States)

    Eksiler, Kubra; Andou, Yoshito; Nakayama, Natsuki; Yoshinaga, Keita; Shirai, Yoshihito

    2017-09-01

    In this study, novel eco-friendly blends based on environmental-friendly polymers and compatibilizers, such as poly(ϵ-caprolactone) (PCL), cis-1,4-polyisoprene (PI), soybean lecithin (SOLE) and acrylated-epoxidized soybean oil (AESO), have been prepared in order to suggest a biodegradable joining tool used for plant grafting in agriculture, which will be competitive from the environment and economic points of view against conventional nonbiodegradable tools. PCL/PI blends, in which the portion of PCL was 75 and 50, were mixed with a compatibilizer by a melt-blending technique. The resulting blends were investigated by thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy and also their mechanical properties were determined. Afterwards, the blend films were buried in the soil. Remarkable level of weight loss was achieved in 6 weeks, ∼46%. The results showed that the addition of SOLE helped to improve the compatibility between PCL and PI due to its amphipathic property, and, besides, accelerated the weight loss of the films in soil, increasing microorganism growth on the film.

  6. All-epiphyseal semitendinosus PCL reconstruction in a 10-year-old child.

    Science.gov (United States)

    Warme, Winston J; Mickelson, Dayne

    2010-01-01

    Tears of the posterior cruciate ligament (PCL) in pediatric patients, especially avulsions from its tibial insertion, are not frequently encountered by physicians. However, with an increasing incidence of ligamentous injuries to the knee in skeletally immature patients, orthopaedic surgeons will more frequently need to decide how best to manage a PCL injury in children with open physes. A 10-year-old boy sustained an avulsion of the PCL from its tibial insertion site after a bicycle motocross racing accident. He required a PCL reconstruction after failed conservative treatment and an unsuccessful attempt at primary repair. This successful physeal sparing reconstruction was accomplished using a modified method of femoral tunnel placement in combination with the tibial inlay technique. A magnetic resonance imaging was acquired 2 years postoperatively when physical examination demonstrated both legs of equal length, no varus or valgus deformity, and a normal posterior drawer examination. Four years after the reconstruction, he continues to bicycle motocross race while experiencing no further symptoms and complete restoration to his prior quality of life. The use of the tibial inlay technique together with the modified femoral tunnel location prevented transphyseal drilling while attaining a favorable anatomic placement of the graft while avoiding the "killer" turn associated with the transtibial approach. Level IV (Therapeutic Study).

  7. Draft Genome Sequence of the Rhizobacterium Pseudomonas chlororaphis PCL1601, Displaying Biocontrol against Soilborne Phytopathogens.

    Science.gov (United States)

    Vida, Carmen; de Vicente, Antonio; Cazorla, Francisco M

    2017-04-06

    In this study, we present the draft genome sequence of the bacterial strain Pseudomonas chlororaphis PCL1601. This bacterium was isolated from the rhizosphere of healthy avocado trees and displayed antagonistic and biological control activities against different soilborne phytopathogenic fungi and oomycetes. Copyright © 2017 Vida et al.

  8. Vascular Tissue Engineering: Effects of Integrating Collagen into a PCL Based Nanofiber Material

    Directory of Open Access Journals (Sweden)

    Ulf Bertram

    2017-01-01

    Full Text Available The engineering of vascular grafts is a growing field in regenerative medicine. Although numerous attempts have been made, the current vascular grafts made of polyurethane (PU, Dacron®, or Teflon® still display unsatisfying results. Electrospinning of biopolymers and native proteins has been in the focus of research to imitate the extracellular matrix (ECM of vessels to produce a small caliber, off-the-shelf tissue engineered vascular graft (TEVG as a substitute for poorly performing PU, Dacron, or Teflon prostheses. Blended poly-ε-caprolactone (PCL/collagen grafts have shown promising results regarding biomechanical and cell supporting features. In order to find a suitable PCL/collagen blend, we fabricated plane electrospun PCL scaffolds using various collagen type I concentrations ranging from 5% to 75%. We analyzed biocompatibility and morphological aspects in vitro. Our results show beneficial features of collagen I integration regarding cell viability and functionality, but also adverse effects like the loss of a confluent monolayer at high concentrations of collagen. Furthermore, electrospun PCL scaffolds containing 25% collagen I seem to be ideal for engineering vascular grafts.

  9. Paediatric physeal sparing posterior cruciate ligament (PCL) reconstruction with parental donation allograft: Rationale and operative approach.

    Science.gov (United States)

    Khakha, R S; Yasen, S K; Wilson, A J

    2018-01-14

    Paediatric PCL injuries are rare but constitute a significant management challenge. We describe a novel approach to the surgical management of an 11-year-old boy who presented with persisting symptomatic instability following 18months of failed conservative therapy. PCL reconstruction was performed using a physeal sparing, all-inside technique under fluoroscopic control. This avoids the potential for iatrogenic growth injury. A parentally donated hamstrings allograft was used to ensure adequate graft size, and reinforced using a non-elastic two millimetre braided suture. Graft reinforcement safeguards against stretching during the early healing phase, but must be removed thereafter to avoid creating a physeal tether. At three months, clinical examination under anaesthesia showed equivalent PCL laxity in the operated knee compared to the normal contralateral knee. The graft reinforcement tape was incised as planned with no change in laxity assessment. Arthroscopic evaluation demonstrated a quiet joint with a well healed graft and no synovitis. Postoperative long leg radiographs showed no growth deformity against preoperative status. In paediatric patients with persisting symptomatic instability despite appropriate conservative management, surgical reconstruction of the PCL should be considered. Standard treatment has higher complication rates and poorer graft survival than in an adult cohort. Specific problems include iatrogenic growth plate injury causing growth arrest or angular deformity, inadequate graft size if using hamstrings autograft, and the additional technical challenge of small patient size. Early results from extra-physeal, all-inside PCL reconstruction using a parentally donated allograft are promising and may provide an alternative solution to traditional surgical management. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Electrospinning PCL Scaffolds Manufacture for Three-Dimensional Breast Cancer Cell Culture

    Directory of Open Access Journals (Sweden)

    Marc Rabionet

    2017-08-01

    Full Text Available In vitro cell culture is traditionally performed within two-dimensional (2D environments, providing a quick and cheap way to study cell properties in a laboratory. However, 2D systems differ from the in vivo environment and may not mimic the physiological cell behavior realistically. For instance, 2D culture models are thought to induce cancer stem cells (CSCs differentiation, a rare cancer cell subpopulation responsible for tumor initiation and relapse. This fact hinders the development of therapeutic strategies for tumors with a high relapse percentage, such as triple negative breast cancer (TNBC. Thus, three-dimensional (3D scaffolds have emerged as an attractive alternative to monolayer culture, simulating the extracellular matrix structure and maintaining the differentiation state of cells. In this work, scaffolds were fabricated through electrospinning different poly(ε-caprolactone-acetone solutions. Poly(ε-caprolactone (PCL meshes were seeded with triple negative breast cancer (TNBC cells and 15% PCL scaffolds displayed significantly (p < 0.05 higher cell proliferation and elongation than the other culture systems. Moreover, cells cultured on PCL scaffolds exhibited higher mammosphere forming capacity and aldehyde dehydrogenase activity than 2D-cultured cells, indicating a breast CSCs enrichment. These results prove the powerful capability of electrospinning technology in terms of poly(ε-caprolactone nanofibers fabrication. In addition, this study has demonstrated that electrospun 15% PCL scaffolds are suitable tools to culture breast cancer cells in a more physiological way and to expand the niche of breast CSCs. In conclusion, three-dimensional cell culture using PCL scaffolds could be useful to study cancer stem cell behavior and may also trigger the development of new specific targets against such malignant subpopulation.

  11. Sequential crystallization and morphology of triple crystalline biodegradable PEO-b-PCL-b-PLLA triblock terpolymers

    KAUST Repository

    Palacios, Jordana

    2016-01-05

    The sequential crystallization of poly(ethylene oxide)-b-poly(e-caprolactone)-b-poly(L-lactide) (PEO-b-PCL-b-PLLA) triblock terpolymers, in which the three blocks are able to crystallize separately and sequentially from the melt, is presented. Two terpolymers with identical PEO and PCL block lengths and two different PLLA block lengths were prepared, thus the effect of increasing PLLA content on the crystallization behavior and morphology was evaluated. Wide angle X-Ray scattering (WAXS) experiments performed on cooling from the melt confirmed the triple crystalline nature of these terpolymers and revealed that they crystallize in sequence: the PLLA block crystallizes first, then the PCL block, and finally the PEO block. Differential scanning calorimetry (DSC) analysis further demonstrated that the three blocks can crystallize from the melt when a low cooling rate is employed. The crystallization process takes place from a homogenous melt as indicated by small angle X-Ray scattering (SAXS) experiments. The crystallization and melting enthalpies and temperatures of both PEO and PCL blocks decrease as PLLA content in the terpolymer increases. Polarized light optical microscopy (PLOM) demonstrated that the PLLA block templates the morphology of the terpolymer, as it forms spherulites upon cooling from the melt. The subsequent crystallization of PCL and PEO blocks occurs inside the interlamellar regions of the previously formed PLLA block spherulites. In this way, unique triple crystalline mixed spherulitic superstructures have been observed for the first time. As the PLLA content in the terpolymer is reduced the superstructural morphology changes from spherulites to a more axialitic-like structure.

  12. Initial and delayed stress phase imaging in a single-injection double-acquisition SPECT. The potential value of early {sup 99m}Tc-MIBI redistribution in assessment of myocardial perfusion reversibility in patients with coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Beiki, D. [Research Inst. for Nuclear Medicine, Tehran Univ. of Medical Sciences, Tehran (Iran); Dept. of Nuclear Pharmacy, Tehran Univ. of Medical Sciences, Tehran (Iran); Fallahi, B.; Fard-Esfahani, A.; Eftekhari, M. [Research Inst. for Nuclear Medicine, Tehran Univ. of Medical Sciences, Tehran (Iran); Mohseni, Z.; Khalaj, A. [Dept. of Nuclear Pharmacy, Tehran Univ. of Medical Sciences, Tehran (Iran)

    2010-07-01

    Some studies reported that {sup 99m}Tc-MIBI may redistribute in ischaemic myocardium and this phenomenon may have potential role for better assessment of viability by delayed {sup 99m}Tc-MIBI imaging. Some studies also suggested that infusion of low dose dobutamine during delayed imaging may enhance the value of {sup 99m}Tc-MIBI imaging for evaluation of viability. The aim of this study is to determine whether the observed changes of perfusion defects on delayed images are caused by early radiotracer redistribution or as a result of reversal partial volume effect secondary to inotropic stimulation. Patients, methods: 89 patients with angiographically proven coronary artery disease (CAD) were enrolled in this randomized clinical trial study. In all cases, gated-SPECT images were obtained 60 minutes after stress with dipyridamole injection. Subsequently the patients were randomly allocated in two groups and the second imaging was performed at 120{sup th} minute during low dose dobutamine (dobutamine group; 45 cases) or placebo infusion (placebo group; 44 cases). Difference between summed stress score of the first (SSS{sub 1}) and second (SSS{sub 2}) stress images ({delta}SSS) was considered as a marker of reversibility in single-injection double-acquisition (SIDA) protocol. Also summed difference score (SDS) was recorded as a marker of reversibility in standard stress/rest, double-injection double-acquisition (DIDA) protocol. {delta}SSS of the two studied groups were compared. Also the correlation and agreement between {delta}SSS and SDS were analyzed. Results: A significant difference was found between SSS{sub 1} (median 15, range 0-48) and SSS{sub 2} (median 11, range 0-42) in total patients (p < 0.0001). A significant correlation was noted between {delta}SSS and SDS in dobutamine group (r = 0.58, p = 0.002) as well as in placebo group (r = 0.57, p < 0.0001). Considering DIDA protocol as a standard reference method, the influence of dobutamine infusion was not

  13. 2-N, 6-O-sulfated chitosan-assisted BMP-2 immobilization of PCL scaffolds for enhanced osteoinduction.

    Science.gov (United States)

    Cao, Lingyan; Yu, Yuanman; Wang, Jing; Werkmeister, Jerome A; McLean, Keith M; Liu, Changsheng

    2017-05-01

    The aim of this study was to develop a 2-N, 6-O-sulfated chitosan (26SCS) modified electrospun fibrous PCL scaffold for bone morphogenetic protein-2 (BMP-2) delivery to improve osteoinduction. The PCL scaffold was modified by an aminolysis reaction using ethylenediamine (ED) and 26SCS was immobilized via electrostatic interactions (PCL-N-S). Scaffolds were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. In vitro BMP-2 adsorption and release kinetics indicated that modified PCL-N-S scaffolds showed higher levels of binding of BMP-2 (about 30-100 times), moderative burst release (about one third), and prolonged releasing time compared to the unmodified PCL scaffold. The bioactivity of released BMP-2 determined by alkaline phosphatase (ALP) activity assay was maintained and improved 8-12 times with increasing concentration of immobilized 26SCS on the scaffolds. In vitro studies demonstrated that bone marrow mesenchymal stem cells (BMSCs) attached more readily to the PCL-N-S scaffolds with increased spreading. In conclusion, 26SCS modified PCL scaffolds can be a potent system for the sustained and bioactive delivery of BMP-2. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Enhanced adhesion and proliferation of human umbilical vein endothelial cells on conductive PANI-PCL fiber scaffold by electrical stimulation.

    Science.gov (United States)

    Li, Yumei; Li, Xiang; Zhao, Rui; Wang, Chuying; Qiu, Fangping; Sun, Bolun; Ji, He; Qiu, Ju; Wang, Ce

    2017-03-01

    Recently, electrically conductive biomaterial scaffolds have shown great potential in tissue regeneration. Herein, we reported an electrically conductive polyaniline (PANI) coated poly(ε-caprolactone) (PCL) electrospun micron-fiber scaffold for the enhanced attachment and proliferation of human umbilical vein endothelial cells (HUVECs) under electrical stimulation conditions. After the O2 plasma treatment toward PCL electrospun fiber, PANI could be polymerized onto their surfaces successfully. The obtained PANI-PCL fibers were characterized by SEM observations, FT-IR spectra, XPS analysis, and water contact angle measurement. The mechanical tests indicated that the fibers could satisfy the practical vascular scaffold requirements. The conductivity of the PANI-PCL fibers was 6.71×10-3S/cm which could provide a conductive in-vitro platform to study the effect of electrical stimulation on HUVECs proliferation. When PANI-coated PCL fibers were compared with PCL fibers, HUVECs exhibited highly enhanced adhesion and viability, especially under electrical stimulation (ES) of 200, 300, and 400mV/cm. Proliferation of HUVECs on PANI-PCL fibers was strongly dependent on electrical stimulation intensity. The results showed new insights into conductive scaffolds for vascular tissue engineering. Copyright © 2016. Published by Elsevier B.V.

  15. Effects of Chitosan Alkali Pretreatment on the Preparation of Electrospun PCL/Chitosan Blend Nanofibrous Scaffolds for Tissue Engineering Application

    Directory of Open Access Journals (Sweden)

    Fatemeh Roozbahani

    2013-01-01

    Full Text Available Recently, nanofibrous scaffolds have been used in the field of biomedical engineering as wound dressings, tissue engineering scaffolds, and drug delivery applications. The electrospun nanofibrous scaffolds can be used as carriers for several types of drugs, genes, and growth factors. PCL is one of the most commonly applied synthetic polymers for medical use because of its biocompatibility and slow biodegradability. PCL is hydrophobic and has no cell recognition sites on its structure. Electrospinning of chitosan and PCL blend was investigated in formic acid/acetic acid as the solvent with different PCL/chitosan ratios. High viscosity of chitosan solutions makes difficulties in the electrospinning process. Strong hydrogen bonds in a 3D network in acidic condition prevent the movement of polymeric chains exposed to the electrical field. Consequently, the amount of chitosan in PCL/chitosan blend was limited and more challenging when the concentration of PCL increases. The treatment of chitosan in alkali condition under high temperature reduced its molecular weight. Longer treatment time further decreased the molecular weight of chitosan and hence its viscosity. Electrospinning of PCL/chitosan blend was possible at higher chitosan ratio, and SEM images showed a decrease in fiber diameter and narrower distribution with increase in the chitosan ratio.

  16. Structure and magnetic properties of SiO{sub 2}/PCL novel sol–gel organic–inorganic hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, Michelina, E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Cristina Mozzati, Maria [Department of Physics, CNISM and INSTM, University of Pavia, Via Bassi 6, 27100 Pavia (Italy); Ferrara, Chiara; Mustarelli, Piercarlo [Department of Chemistry, Section of Physical Chemistry, University of Pavia and INSTM, Via Taramelli 16, 27100 Pavia (Italy)

    2013-07-15

    Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO{sub 2} matrix, in which different percentages of poly(ε-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunity to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO{sub 2}/PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount. - Graphical abstract: Characterization and magnetic properties of SiO{sub 2}/PCL organic–inorganic hybrid materials synthesized via sol–gel. FT-IR, Fourier transform infrared spectroscopy; solid-state NMR: solid-state nuclear magnetic resonance; SQUID: superconducting quantum interference device. - Highlights: • Sol–gel synthesis of SiO{sub 2}/PCL amorphous class I organic–inorganic hybrid materials. • FT-IR and NMR analyses show the hydrogen bonds formation between SiO{sub 2} and PCL. • AFM and SEM analyses confirm that the SiO{sub 2}/PCL are homogenous hybrid materials. • The SQUID measures show that the simples are diamagnetic. • Diamagnetic susceptibility of SiO{sub 2}/PCL materials increases with the PCL amount.

  17. Posterior tibial displacement in the PCL-deficient knee is reduced compared to the normal knee during gait.

    Science.gov (United States)

    Orita, Naoya; Deie, Masataka; Shimada, Noboru; Iwaki, Daisuke; Asaeda, Makoto; Hirata, Kazuhiko; Ochi, Mitsuo

    2015-11-01

    Most individuals with an isolated posterior cruciate ligament (PCL) injury do not complain of disability even if posterior instability is objectively revealed by a static physical examination, such as the posterior drawer test. This suggests it is insufficient to only evaluate posterior instability under static conditions. Therefore, we have investigated the effect of isolated PCL injury on the detailed kinematics of the knee in a dynamic environment such as during gait. Eight unilateral PCL-deficient males and eight healthy control volunteers participated in this study. Isolated PCL injury was diagnosed by clinical examination. Stress X-ray imaging showed an average side-to-side difference of 12.7 ± 3.5 mm. Knee kinematics including anteroposterior tibial displacement were analysed during walking using the point cluster technique. Posterior tibial displacement from initial contact was significantly smaller during 9-22 % of the gait cycle by an average of 0.4 cm in the PCL group, compared to controls. In the PCL-deficient knee, the external rotational angle increased by an average of 3.3° at the loading response during 3-11 % of the gait cycle and the varus angle from initial contact increased by an average of 2.0° during 28-52 % of the gait cycle, compared to controls. Dynamic changes in the rotation and posterior translation patterns were seen after isolated PCL injury, suggesting the kinematics of PCL-deficient knees might be different to normal knees. These factors may contribute to long-term osteoarthritic change. Consequently, when choosing conservative treatment for PCL injury, these changes should be considered to prevent osteoarthritic change. III.

  18. Initiation of HIV Reverse Transcription

    Directory of Open Access Journals (Sweden)

    Roland Marquet

    2010-01-01

    Full Text Available Reverse transcription of retroviral genomes into double stranded DNA is a key event for viral replication. The very first stage of HIV reverse transcription, the initiation step, involves viral and cellular partners that are selectively packaged into the viral particle, leading to an RNA/protein complex with very specific structural and functional features, some of which being, in the case of HIV-1, linked to particular isolates. Recent understanding of the tight spatio-temporal regulation of reverse transcription and its importance for viral infectivity further points toward reverse transcription and potentially its initiation step as an important drug target.

  19. How the Complex Interplay between Different Blocks Determines the Isothermal Crystallization Kinetics of Triple-Crystalline PEO-b-PCL-b-PLLA Triblock Terpolymers

    KAUST Repository

    Palacios, Jordana K.

    2017-12-05

    PEO-b-PCL-b-PLLA triblock terpolymers are fascinating triple-crystalline materials. In this work, the isothermal crystallization kinetics of these terpolymers evaluated by differential scanning calorimetry (DSC) is presented for the first time and compared to analogous PCL-b-PLLA diblock copolymers and to PLLA, PCL, and PEO homopolymers. The results are complemented by in situ SAXS/WAXS synchrotron experiments. One-, two-, and three-step crystallization protocols were employed to study the crystallization kinetics of the blocks. At PLLA block crystallization temperatures, both PCL and PEO molten chains caused a strong plasticizing effect on the PLLA block crystallization, and the overall crystallization rate of the PLLA block in the terpolymers was higher than that in the PLLA-b-PCL diblock copolymers. In the case of the PCL block, the crystallization was followed after PLLA was fully crystallized (two-step crystallization). A nucleating effect induced by the previously formed PLLA crystals was observed. However, an antiplasticizing effect on PCL crystallization was detected if the sample is quenched directly from the melt to the PCL crystallization temperature (one-step crystallization). Finally, the crystallization of the PEO block was followed after PLLA and PCL had fully crystallized (three-step crystallization). The PEO crystallization rate highly decreased due to the confinement imposed by the previously formed PLLA and PCL crystals. Complex competitive effects such as plasticization, nucleation, antiplasticization, and confinement occurred during the isothermal crystallization of tricrystalline PEO-b-PCL-b-PLLA triblock terpolymers.

  20. Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

    Science.gov (United States)

    Surucu, Seda; Masur, Kai; Turkoglu Sasmazel, Hilal; Von Woedtke, Thomas; Weltmann, Klaus Dieter

    2016-11-01

    This paper reports Ar gas, Ar + O2, Ar + O2 + N2 gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O2 + N2 gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O2 + N2 gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on/within scaffolds.

  1. The Osteogenic Differentiation Effect of the FN Type 10-Peptide Amphiphile on PCL Fiber

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    Ye-Rang Yun

    2018-01-01

    Full Text Available The fibronectin type 10-peptide amphiphile (FNIII10-PA was previously genetically engineered and showed osteogenic differentiation activity on rat bone marrow stem cells (rBMSCs. In this study, we investigated whether FNIII10-PA demonstrated cellular activity on polycaprolactone (PCL fibers. FNIII10-PA significantly increased protein production and cell adhesion activity on PCL fibers in a dose-dependent manner. In cell proliferation results, there was no effect on cell proliferation activity by FNIII10-PA; however, FNIII10-PA induced the osteogenic differentiation of MC3T3-E1 cells via upregulation of bone sialoprotein (BSP, collagen type I (Col I, osteocalcin (OC, osteopontin (OPN, and runt-related transcription factor 2 (Runx2 mitochondrial RNA (mRNA levels; it did not increase the alkaline phosphatase (ALP mRNA level. These results indicate that FNIII10-PA has potential as a new biomaterial for bone tissue engineering applications.

  2. Mechanical properties of electrospun PCL scaffold under in vitro and accelerated degradation conditions

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Vange, Jakob; Nielsen, Lene Feldskov

    2014-01-01

    ) with and without the influence of cell in-growth. The molecular weight and mechanical properties were monitored during the degradation. Incubation in physiological fluids for 3–16 weeks showed an improvement in mechanical properties and no reduction in molecular weight. It was also shown that cells did...... not deteriorate the mechanical properties of PCL after 16 weeks. The viability of the cells decreased over time, however, without influencing the mechanical properties of the scaffold. A relation between reduction in molecular weight and the mechanical properties of electrospun PCL was seen between 2–29 days...... in buffer (pH 12). The accelerated study showed a linear decrease in both elastic modulus and yield stress as a function of degradation time....

  3. Astrocyte behavior and GFAP expression on Spirulina extract-incorporated PCL nanofiber.

    Science.gov (United States)

    Min, Seul Ki; Kim, Cho Rong; Jung, Sang Myung; Shin, Hwa Sung

    2013-12-01

    Nanomaterials are attractive for use in biological systems due to their ability to control the microenvironment of cells. Additionally, nanofibers can mimic fibrous characteristics of natural tissues. This study was conducted to assess astrocyte activity and infiltration behavior on Spirulina extract-embedded polycaprolactone (SP-PCL) nanofiber. Astrocytes moved along with the nanofiber, and developed an elongated and stellate shape, which is similar to those in the natural neural tissue. In addition, the expression of GFAP, a biomarker representing the activation of astrocytes, was gradually up-regulated with the increase of the concentration of Spirulina extract, indicating that Spirulina extract can control astrocyte activation. Overall, the results presented herein indicate that SP-PCL nanofiber could be used in astrocyte tissue engineering for neuronal regeneration. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  4. Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Rosario, F. [Faculdade de Tecnologia da Zona Leste (FATEC-ZL), Sao Paulo, SP (Brazil). Centro Paulo Souza; Casarin, S.A.; Agnelli, J.A.M. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Souza Junior, O.F. de [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2010-07-01

    This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

  5. Precision extruding deposition (PED) fabrication of polycaprolactone (PCL) scaffolds for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shor, Lauren; Gueceri, Selcuk; Chang, Robert; Sun Wei [Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA (United States); Gordon, Jennifer; Kang Qian; Hartsock, Langdon; An Yuehuei [Department of Orthopedic Surgery, Medical University of South Carolina, Charleston, SC (United States)], E-mail: st963bya@drexel.edu, E-mail: guceri@drexel.edu, E-mail: rcc34@drexel.edu, E-mail: sunwei@drexel.edu, E-mail: kangqk@musc.edu, E-mail: hartsock@musc.edu, E-mail: any@musc.edu

    2009-03-01

    Bone tissue engineering is an emerging field providing viable substitutes for bone regeneration. Recent advances have allowed scientists and engineers to develop scaffolds for guided bone growth. However, success requires scaffolds to have specific macroscopic geometries and internal architectures conducive to biological and biophysical functions. Freeform fabrication provides an effective process tool to manufacture three-dimensional porous scaffolds with complex shapes and designed properties. A novel precision extruding deposition (PED) technique was developed to fabricate polycaprolactone (PCL) scaffolds. It was possible to manufacture scaffolds with a controlled pore size of 350 {mu}m with designed structural orientations using this method. The scaffold morphology, internal micro-architecture and mechanical properties were evaluated using scanning electron microscopy (SEM), micro-computed tomography (micro-CT) and mechanical testing, respectively. An in vitro cell-scaffold interaction study was carried out using primary fetal bovine osteoblasts. Specifically, the cell proliferation and differentiation was evaluated by Alamar Blue assay for cell metabolic activity, alkaline phosphatase activity and osteoblast production of calcium. An in vivo study was performed on nude mice to determine the capability of osteoblast-seeded PCL to induce osteogenesis. Each scaffold was implanted subcutaneously in nude mice and, following sacrifice, was explanted at one of a series of time intervals. The explants were then evaluated histologically for possible areas of osseointegration. Microscopy and radiological examination showed multiple areas of osseous ingrowth suggesting that the osteoblast-seeded PCL scaffolds evoke osteogenesis in vivo. These studies demonstrated the viability of the PED process to fabricate PCL scaffolds having the necessary mechanical properties, structural integrity, and controlled pore size and interconnectivity desired for bone tissue engineering.

  6. Mechanical fatigue performance of PCL-chondroprogenitor constructs after cell culture under bioreactor mechanical stimulus.

    Science.gov (United States)

    Panadero, Juan Alberto; Sencadas, Vitor; Silva, Sonia C M; Ribeiro, Clarisse; Correia, Vitor; Gama, Francisco M; Gomez Ribelles, José Luis; Lanceros-Mendez, Senentxu

    2016-02-01

    In tissue engineering of cartilage, polymeric scaffolds are implanted in the damaged tissue and subjected to repeated compression loading cycles. The possibility of failure due to mechanical fatigue has not been properly addressed in these scaffolds. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading-unloading cycles. This is related to inherent discontinuities in the material due to the micropore structure of the macro-pore walls that act as stress concentration points. In this work, chondrogenic precursor cells have been seeded in poly-ε-caprolactone (PCL) scaffolds with fibrin and some were submitted to free swelling culture and others to cyclic loading in a bioreactor. After cell culture, all the samples were analyzed for fatigue behavior under repeated loading-unloading cycles. Moreover, some components of the extracellular matrix (ECM) were identified. No differences were observed between samples undergoing free swelling or bioreactor loading conditions, neither respect to matrix components nor to mechanical performance to fatigue. The ECM did not achieve the desired preponderance of collagen type II over collagen type I which is considered the main characteristic of hyaline cartilage ECM. However, prediction in PCL with ECM constructs was possible up to 600 cycles, an enhanced performance when compared to previous works. PCL after cell culture presents an improved fatigue resistance, despite the fact that the measured elastic modulus at the first cycle was similar to PCL with poly(vinyl alcohol) samples. This finding suggests that fatigue analysis in tissue engineering constructs can provide additional information missed with traditional mechanical measurements. © 2015 Wiley Periodicals, Inc.

  7. PSMA ligand conjugated PCL-PEG polymeric micelles targeted to prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Jian Jin

    Full Text Available In this content, a small molecular ligand of prostate specific membrane antigen (SMLP conjugated poly (caprolactone (PCL-b-poly (ethylene glycol (PEG copolymers with different block lengths were synthesized to construct a satisfactory drug delivery system. Four different docetaxel-loaded polymeric micelles (DTX-PMs were prepared by dialysis with particle sizes less than 60 nm as characterized by dynamic light scattering (DLS and transmission electron microscope (TEM. Optimization of the prepared micelles was conducted based on short-term stability and drug-loading content. The results showed that optimized systems were able to remain stable over 7 days. Compared with Taxotere, DTX-PMs with the same ratio of hydrophilic/hydrophobic chain length displayed similar sustained release behaviors. The cytotoxicity of the optimized targeted DTX-PCL12K-PEG5K-SMLP micelles (DTX-PMs2 and non-targeted DTX-PCL12K-mPEG5K micelles (DTX-PMs1 were evaluated by MTT assays using prostate specific membrane antigen (PSMA positive prostate adenocarcinoma cells (LNCaP. The results showed that the targeted micelles had a much lower IC50 than their non-targeted counterparts (48 h: 0.87 ± 0.27 vs 13.48 ± 1.03 µg/ml; 72 h: 0.02 ± 0.008 vs 1.35 ± 0.54 µg/ml. In vitro cellular uptake of PMs2 showed 5-fold higher fluorescence intensity than that of PMs1 after 4 h incubation. According to these results, the novel nano-sized drug delivery system based on DTX-PCL-PEG-SMLP offers great promise for the treatment of prostatic cancer.

  8. PCL assay application in superoxide anion-radical scavenging capacity of tea Camellia sinensis extracts.

    Science.gov (United States)

    Gramza-Michałowska, Anna; Sidor, Andrzej; Reguła, Julita; Kulczyński, Bartosz

    2015-01-01

    Plant polyphenols are known for their limiting of adverse effects on reactive oxygen species (ROS) in biological systems. The photochemiluminescence (PCL) assay allows to evaluate the antiradical activity of a compound in the presence of a superoxide anion-radical (O •-), which is one of the ROS directly associated with the human body. In this work, determination of the superoxide anion radical scavenging activity of different tea extracts using the PCL assay was performed. Investigations were conducted on different tea leaves extracts. The study included five kinds of tea leaves subjected to aqueous and ethanol extraction procedure. Catechins content was evaluated using HPLC. Antiradical activity of the samples was conducted with use of Photochem assay. Analysis of total catechins content in tea aqueous extracts enabled them to be arranged as follows: yellow > green > white > red > black, while for ethanol extracts it was: yellow = green > white > red > black. The examined tea extracts were ranked from highest to lowest water-soluble antioxidative capacity (ACW) values as follows: yellow > green > white > red > black. The results of lipid-soluble antioxidative capacity (ACL) values for aqueous extracts were similar; however, were approximately 50% lower than those presented as ACW. The second examined group were ethanol extracts, which ranked for ACW values: yellow > green = red = white > black, while ACL values ranked as follows: yellow > white = black = red > green. PCL assay results were correlated with total catechin content in aqueous extracts. Antiradical activity of different tea leaves extracts in PCL assay, showed that the highest activity was found in extracts of yellow tea; the lowest, however, was identified in black tea extracts.

  9. PENERAPAN MODEL PROJECT CREATIVE LEARNING (PCL UNTUK MENGEMBANGKAN KETERAMPILAN BERPIKIR KREATIF KONSEP LISTRIK MAGNET

    Directory of Open Access Journals (Sweden)

    F. C. Wibowo

    2013-07-01

    Full Text Available ABSTRAKTelah dilakukan studi eksperimen tentang penerapan model Project Creative  Learning (PCL untuk mengembangkan keterampilan berpikir kreatif pada konsep listrik magnet. Tujuan studi ini adalah untuk mendapatkan gambaran tentang peningkatan keterampilan berpikir kreatif sebagai dampak penerapan model. Metode penelitian yang digunakan eksperimental dengan desain two group pretest-posttest. Subyek penelitian mahasiswa semester 2 (dua di salah satu Universitas Swasta di Kota Semarang, Jawa Tengah. Instrumen penelitian terdiri dari tes keterampilan berpikir kreatif. Hasil penelitian menunjukkan bahwa setelah penerapan model pembelajaran sebagian keterampilan berpikir kreatif tinggi. Hal ini diindikasikan oleh rata-rata skor gain yang dinormalisasi keterampilan berpikir kreatif pada kelompok eksperimen 1 meningkat sebesar 0,72 dan pada kelompok eksperimen 2 meningkat sebesar 0,74. Hasil ini menunjukkan bahwa model PCL merupakan salah satu model pembelajaran yang dapat meningkatkan keterampilan berpikir kreatif. ABSTRACTExperimental studies have been conducted on the implementation of the model of Project of Creative Learning (PCL to develop creative thinking skills of concept of electricity and magnetism.This study aimed at determining the increase of creative thinking skills as a result of the implementation of the model. Research method used was experimental method with design of two group pretest-posttest. The research subject was students of semester 2 (two of one of private universities in the city of Semarang, Central Java. The research instrument used creative thinking skills test. The result showed that after getting the implementation of project-based learning model, most of the creative thinking skills were high. It was indicated by the average score of normalized gain of creative thinking skill of first experiment group  which increased by 0.72 and those for second experiment groups which increased by 0.74. These results

  10. The influence of soil and landfill leachate microorganisms in the degradation of PVC/PCL films cast from DMF

    Directory of Open Access Journals (Sweden)

    Adriana de Campos

    2012-01-01

    Full Text Available While the use of plastics continues to increase in our daily lives in a growing range products, these materials are very persistent in the environment. The blending of aliphatic polyesters with other thermoplastic polymers is a profitable way of producing materials with changed physical properties and biodegradability, which can facilitate microbial adhesion to the polymer matrix and help to reduce (post-consumer degradation time of these materials in landfills. This study was an investigation of the biodegradation of films of blends of poly(vinyl chloride (PVC and poly(ε-caprolactone (PCL by soil microorganisms and leachate, by means of respirometry, infrared absorption spectroscopy (FTIR, differential calorimetry scanning (DSC, scanning electron microscopy (SEM, contact angle and weight loss. The results showed that in the soil, the films suffered oxidative biodegradation. The PCL promoted degradation of the PVC in the film of PVC/PCL and the PVC inhibited the rapid degradation of the PCL.

  11. Development of a PCL-silica nanoparticles composite membrane for Guided Bone Regeneration.

    Science.gov (United States)

    Castro, Antonio G B; Diba, Mani; Kersten, Monique; Jansen, John A; van den Beucken, Jeroen J J P; Yang, Fang

    2018-04-01

    The pivotal step in Guided Bone Regeneration (GBR) therapy is the insertion of a membrane for support and barrier functions. Here, we studied the effect of the addition of silica nanoparticles (Si-NPs) in electrospun poly(ε-caprolactone) (PCL) membranes to improve the mechanical and osteoconductive properties of the membranes. To this end, Si-NPs were firstly synthesized and then suspended in PCL solutions containing a polar solvent (2,2,2-trifluroethanol) and water with the addition of an anionic surfactant. Nanocomposite membranes were fabricated from the solutions through an electrospinning technique. Morphology, structure and chemical composition, and tensile properties of the membranes were analyzed. Membrane stability was determined by visual examination of the membranes after immersion in phosphate buffered saline. The effect of the materials on osteoblastic differentiation was evaluated by in vitro culture of the membranes with MC3T3-E1 osteoblastic cells. The results indicated that Si-NPs were successfully incorporated in the interior of the PCL electrospun fibers during the electrospinning process. Tensile modulus was significantly increased for composition S50 and tensile strength significantly increased for compositions S25 and S50. Membranes containing Si-NPs have shown to be cytocompatible. The results obtained demonstrate that the Si-NPs were homogeneously incorporated in the electrospun fibers, resulting in an improvement of the tensile properties of the prepared materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Assessment of PTSD in Older Veterans: The Posttraumatic Stress Disorder Checklist: Military Version (PCL-M

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Yarvis

    2012-04-01

    Full Text Available The Posttraumatic Stress Disorder (PTSD Checklist: Military Version (PCL-M is a 17-item, self-report measure of PTSD symptomatology in military veterans and provides one total score and four subscale scores for older veterans’ PTSD (re-experiencing, avoiding, numbing, and hyperarousal symptoms. Study subjects are 456 male veterans over 55-years old with deployed experiences selected from a larger survey data by Veterans’ Affairs Canada (VAC. This study found that overall scale reliability was excellent with alpha of .93 and subscale alphas ranging from .81 to .90. Confirmatory Factor Analysis (CFA confirmed the best fit of four first-order factor models. Criterion validity was confirmed through significant associations of the PCL-M scores with well-established measures of depression, substance abuse, and general health indices. The PCL-M is recommended as a reliable and valid tool for the clinical and empirical assessment of screening PTSD symptomatology, specifically related to older veterans military experiences.

  13. Cotton fabric functionalisation with menthol/PCL micro- and nano-capsules for comfort improvement.

    Science.gov (United States)

    Mossotti, Raffaella; Ferri, Ada; Innocenti, Riccardo; Zelenková, Tereza; Dotti, Francesca; Marchisio, Daniele L; Barresi, Antonello A

    2015-01-01

    Cotton functionalisation with poly-ɛ-caprolactone (PCL) micro- and nano-capsules containing menthol was carried out with the aim of introducing a long-lasting refreshing sensation. The preparation of the polymer micro- and nano-capsules was carried out by solvent displacement technique. A confined impinging jets mixer was used in order to ensure fast mixing and generate a homogeneous environment where PCL and menthol can self-assemble. The micro- and nano-capsules and the functionalised fabrics were characterised by means of DSC, FT-IR spectroscopy and SEM imaging. Micro- and nano-capsules of different size, from about 200 to about 1200 nm, were obtained varying menthol to PCL ratio (from 0.76 to 8), overall concentration and flow rate (i.e. mixing conditions). The inclusion of menthol was confirmed by DSC analysis. A patch test was carried out by 10 volunteers. Micro-capsules were found to be effective in conferring the fabric a refreshing sensation without altering skin physiology.

  14. PCL-coated hydroxyapatite scaffold derived from cuttlefish bone: In vitro cell culture studies

    Energy Technology Data Exchange (ETDEWEB)

    Milovac, Dajana, E-mail: dmilovac@fkit.hr [Faculty of Chemical Engineering and Technology, University of Zagreb (Croatia); Gamboa-Martínez, Tatiana C. [Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València (Spain); Ivankovic, Marica [Faculty of Chemical Engineering and Technology, University of Zagreb (Croatia); Gallego Ferrer, Gloria [Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València (Spain); Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, Valencia (Spain); Ivankovic, Hrvoje [Faculty of Chemical Engineering and Technology, University of Zagreb (Croatia)

    2014-09-01

    In the present study, we examined the potential of using highly porous poly(ε-caprolactone) (PCL)-coated hydroxyapatite (HAp) scaffold derived from cuttlefish bone for bone tissue engineering applications. The cell culture studies were performed in vitro with preosteoblastic MC3T3-E1 cells in static culture conditions. Comparisons were made with uncoated HAp scaffold. The attachment and spreading of preosteoblasts on scaffolds were observed by Live/Dead staining Kit. The cells grown on the HAp/PCL composite scaffold exhibited greater spreading than cells grown on the HAp scaffold. DNA quantification and scanning electron microscopy (SEM) confirmed a good proliferation of cells on the scaffolds. DNA content on the HAp/PCL scaffold was significantly higher compared to porous HAp scaffolds. The amount of collagen synthesis was determined using a hydroxyproline assay. The osteoblastic differentiation of the cells was evaluated by determining alkaline phosphatase (ALP) activity and collagen type I secretion. Furthermore, cell spreading and cell proliferation within scaffolds were observed using a fluorescence microscope. - Highlights: • Hydroxyapatite/poly(ε-caprolactone) scaffold with interconnected pores was prepared • Cytotoxicity test showed that the scaffold was not cytotoxic towards MC3T3-E1 cells • The scaffold supported the attachment, proliferation and differentiation of cells • A 3D cell colonization was confirmed using the fluorescence microscopy • The scaffold might be a promising candidate for bone tissue engineering.

  15. Star-shaped PCL/PLLA blended fiber membrane via electrospinning.

    Science.gov (United States)

    Li, Haotian; Qiao, Tiankui; Song, Ping; Guo, HuiLing; Song, Xiaofeng; Zhang, Baochang; Chen, Xuesi

    2015-01-01

    Electrospun fiber mesh has been a candidate for guided bone regeneration membrane. However, its poor mechanics property has been limited in clinical application. In this study, various star-shaped poly(ε-caprolactones) (PCLs) are successfully synthesized by ring-opening polymerization and mixed with poly(l-lactide) (PLLA) to be made into blended membranes through electrospinning. Their corresponding properties are evaluated including morphology, thermodynamics, mechanics, and cytotoxicity. The blended fibers show smooth surface and well-distributed structure, which have slight differences in morphology with the change of arm number of star-shaped PCL. Crystallization of the fibrous membrane is influenced by star-shaped PCLs. Glass temperature drops from 64.23 °C for pure PLLA membrane to 53.62-49 °C for the blended membranes. The membranous tensile strength is depended strongly on star-shaped PCLs. The tensile strength goes up with arm number increasing; on the contrary, at the same arm number, the mechanics strength decreases with molecular weight increasing. And the fibrous membrane containing 20 wt.% star-shaped PCL shows better mechanics property compared to the other membranes. The star-shaped PCL/PLLA fiber membrane is not cytotoxicity.

  16. Starch/PCL composite nanofibers by co-axial electrospinning technique for biomedical applications.

    Science.gov (United States)

    Komur, B; Bayrak, F; Ekren, N; Eroglu, M S; Oktar, F N; Sinirlioglu, Z A; Yucel, S; Guler, O; Gunduz, O

    2017-03-29

    In this study, starch and polycaprolactone (PCL), composite nanofibers were fabricated by co-axial needle electrospinning technique. Processing parameters such as polymer concentration, flow rate and voltage had a marked influence on the composite fiber diameter. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), mechanical and physical properties (such as density, viscosity and electrical conductivity) of the composite fibres were evaluated. Moreover, a cell culture test was performed in order to determine their cytotoxicity for wound dressing application. The effect of starch ratio in the solution on the properties and morphological structure of the fibers produced was presented. With lower starch concentration values, the fibers have greater ultimate tensile strength characteristic (mostly 4 and 5 wt%). According to SEM results, it can be figured out that the nanofibers fabricated have good spinnability and morphology. The mean diameter of the fibers is about 150 nm. According to results of cell culture study, the finding can be determined that the increase of starch in the fiber also increases the cell viability. Composite nanofibers of starch/PCL have been prepared using a co-axial needle electrospinning technique. PCL was successfully encapsulated within starch. Fiber formation was observed for different ratio of starch. With several test, analysis and measurement performed, some important parameters such as quality and effectuality of each fiber obtained for wound dressing applications were discussed in detail.

  17. Adhesion and metabolic activity of human corneal cells on PCL based nanofiber matrices.

    Science.gov (United States)

    Stafiej, Piotr; Küng, Florian; Thieme, Daniel; Czugala, Marta; Kruse, Friedrich E; Schubert, Dirk W; Fuchsluger, Thomas A

    2017-02-01

    In this work, polycaprolactone (PCL) was used as a basic polymer for electrospinning of random and aligned nanofiber matrices. Our aim was to develop a biocompatible substrate for ophthalmological application to improve wound closure in defects of the cornea as replacement for human amniotic membrane. We investigated whether blending the hydrophobic PCL with poly (glycerol sebacate) (PGS) or chitosan (CHI) improves the biocompatibility of the matrices for cell expansion. Human corneal epithelial cells (HCEp) and human corneal keratocytes (HCK) were used for in vitro biocompatibility studies. After optimization of the electrospinning parameters for all blends, scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and water contact angle were used to characterize the different matrices. Fluorescence staining of the F-actin cytoskeleton of the cells was performed to analyze the adherence of the cells to the different matrices. Metabolic activity of the cells was measured by cell counting kit-8 (CCK-8) for 20days to compare the biocompatibility of the materials. Our results show the feasibility of producing uniform nanofiber matrices with and without orientation for the used blends. All materials support adherence and proliferation of human corneal cell lines with oriented growth on aligned matrices. Although hydrophobicity of the materials was lowered by blending PCL, no increase in biocompatibility or proliferation, as was expected, could be measured. All tested matrices supported the expansion of human corneal cells, confirming their potential as substrates for biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Psychometric properties of the Hare Psychopathy Checklist-Revised (PCL-R) in a representative sample of Canadian federal offenders.

    Science.gov (United States)

    Storey, Jennifer E; Hart, Stephen D; Cooke, David J; Michie, Christine

    2016-04-01

    The Hare Psychopathy Checklist-Revised (PCL-R; Hare, 2003) is a commonly used psychological test for assessing traits of psychopathic personality disorder. Despite the abundance of research using the PCL-R, the vast majority of research used samples of convenience rather than systematic methods to minimize sampling bias and maximize the generalizability of findings. This potentially complicates the interpretation of test scores and research findings, including the "norms" for offenders from the United States and Canada included in the PCL-R manual. In the current study, we evaluated the psychometric properties of PCL-R scores for all male offenders admitted to a regional reception center of the Correctional Service of Canada during a 1-year period (n = 375). Because offenders were admitted for assessment prior to institutional classification, they comprise a sample that was heterogeneous with respect to correctional risks and needs yet representative of all offenders in that region of the service. We examined the distribution of PCL-R scores, classical test theory indices of its structural reliability, the factor structure of test items, and the external correlates of test scores. The findings were highly consistent with those typically reported in previous studies. We interpret these results as indicating it is unlikely any sampling limitations of past research using the PCL-R resulted in findings that were, overall, strongly biased or unrepresentative. (c) 2016 APA, all rights reserved).

  19. Portuguese version of the PTSD Checklist-Military Version (PCL-M)-I: Confirmatory Factor Analysis and reliability.

    Science.gov (United States)

    Carvalho, Teresa; Cunha, Marina; Pinto-Gouveia, José; Duarte, Joana

    2015-03-30

    The PTSD Checklist-Military Version (PCL-M) is a brief self-report instrument widely used to assess Post-traumatic Stress Disorder (PTSD) symptomatology in war Veterans, according to DSM-IV. This study sought out to explore the factor structure and reliability of the Portuguese version of the PCL-M. A sample of 660 Portuguese Colonial War Veterans completed the PCL-M. Several Confirmatory Factor Analyses were conducted to test different structures for PCL-M PTSD symptoms. Although the respecified first-order four-factor model based on King et al.'s model showed the best fit to the data, the respecified first and second-order models based on the DSM-IV symptom clusters also presented an acceptable fit. In addition, the PCL-M showed adequate reliability. The Portuguese version of the PCL-M is thus a valid and reliable measure to assess the severity of PTSD symptoms as described in DSM-IV. Its use with Portuguese Colonial War Veterans may ease screening of possible PTSD cases, promote more suitable treatment planning, and enable monitoring of therapeutic outcomes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Effect of an organoclay on the reaction-induced phase-separation in a dynamically asymmetric epoxy/PCL system

    Directory of Open Access Journals (Sweden)

    J. Rotrekl

    2013-12-01

    Full Text Available The addition of layered silicates can significantly affect the phase behaviour of both immiscible thermoplastic blends and partially miscible thermoset systems that undergo reaction-induced phase separation (RIPS during curing. This study focuses on the phase behaviour of polycaprolactone (PCL/epoxy in the presence of organically modified montmorillonite (oMMT. Due to the high dynamic asymmetry caused by the differences in the molecular weights and viscosities of the PCL and the uncured epoxy, the critical point is localised at low PCL concentrations, as indicated by the pseudophase diagram. The addition of oMMT to the system led to the marked shift of the critical point towards higher concentrations of PCL, with an increase in the oMMT content occurring as a consequence of the preferential localisation of the clay in the epoxy phase, making this phase more dynamically slow. Significant changes in morphology, including phase inversion of the PCL/epoxy systems caused by the presence of oMMT, were recorded for PCL concentrations ranging from 10 to 30%.

  1. Enhanced corrosion resistance and biocompatibility of AZ31 Mg alloy using PCL/ZnO NPs via electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinwoo [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Mousa, Hamouda M. [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Engineering Materials and Mechanical Design, Faculty of Engineering, South Valley University, Qena 83523 (Egypt); Park, Chan Hee, E-mail: biochan@jbnu.ac.kr [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kim, Cheol Sang, E-mail: chskim@jbnu.ac.kr [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2017-02-28

    Highlights: • PCL/ZnO composite coating layer by electrospinning techniques showed the nano-scaled and porous surface structure. • Addition of zinc oxide NPs in the PCL fibers led to enhanced coating adhesion and corrosion resistance. • The composite coated surfaces on Mg substrates improved cell attachment and proliferation. - Abstract: In the efforts to improve corrosion resistance and biocompatibility of magnesium alloys, polycarprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs) composite coatings were applied onto AZ31 Mg alloys via electrospinning technique in this study. The PCL/ZnO composite coatings on Mg alloys were characterized by using FE-SEM, EDX, XPS, and FT-IR. Moreover, coating adhesion test, electrochemical corrosion test, and biocompatibility test in vitro were performed to measure coating performance. Our results revealed that the increase in the content of ZnO NPs in the composite coatings not only improved the coating adhesion of composite coatings on Mg alloys, but also increased the corrosion resistance. Furthermore, the biocompatibility of MC3T3-E1 osteoblasts of the PCL/ZnO composite coated samples was superior to the biocompatibility of the bare samples. Such data suggest that applying PCL/ZnO composite coating to the magnesium alloys has suitable potential in biomedical applications.

  2. Fabricating and controlling PCL electrospun microfibers using filament feeding melt electrospinning technique

    Science.gov (United States)

    Ko, Junghyuk; Ahsani, Vahid; Xiangxiao Yao, Selina; Mohtaram, Nima K.; Lee, Patrick C.; Jun, Martin B. G.

    2017-02-01

    The process of melt electrospinning has received noteworthy attention due to its ability to fabricate micro scaled polymer fibers. Recently, a melt electrospinning process has been attracting attention for biomedical applications, in particular with scaffold fabrication for tissue engineering. In order to enhance cell attachment and proliferation on scaffolds, it is important to control fiber diameters to create an environment to which cells can attach, grow, and proliferate with ease. However, because electrospinning is a process with many parameters, it is particularly difficult to precisely control the diameter of the resulting fibers. Also, polymer powders or pellets melted in nozzles are typically used for melt electrospinning. However, a filament feeding melt electrospinning process has not been yet been implemented. In this study, we developed a melt electrospinning device which can feed PCL (Polycaprolactone, Mw: 80 000 g mol-1) filaments for advanced electrospun fiber diameter control. The PCL filaments were first fabricated by a small scale micro-compounder and then fed into the melting chamber of the electrospinning device. The system was then heated to a desired temperature, and the melt was extruded through a nozzle. The potential difference between the nozzle and counter electrode then drew down the PCL extrudate, creating fine microfibers. Temperature was controlled and monitored via a customized temperature control system. In order to control the dispensing of the PCL filaments, a customized control algorithm using NI (National Instruments) LabVIEW was used. In order to actively cool PCL filaments, a miniature computer fan was attached on the side of the melting chamber so that the filaments would not buckle. This paper reveals the investigation of significant process parameters that influence fiber diameters and their optimization. For instance, applied voltages, distances between the nozzle and a counter electrode, processing temperatures, and

  3. Biodegradação de filmes de PP/PCL em solo e solo com chorume Study of biodegradation of PP/PCL films in soil and soil with leachate landfill

    Directory of Open Access Journals (Sweden)

    Adriana de Campos

    2010-01-01

    Full Text Available Filmes de blenda de poli(ε-caprolactona (PCL e polipropileno (PP foram obtidos por moldagem por compressão. O estudo da biodegradação de filmes de blendas de PP/PCL em solo e solo com chorume foi obtido pela evolução de CO2, perda de massa, ângulo de contato, microscopia eletrônica de varredura (MEV e calorimetria exploratória diferencial (DSC. As análises de evolução de CO2 mostraram que a biodegradação da blenda de PP/PCL em solo com chorume foi maior que a dos homopolímeros, sugerindo que os polímeros na blenda são mais suscetíveis à degradação, o que se deve à não interação entre PP e PCL. Os resultados também mostraram que os microrganismos do solo com chorume provocaram uma erosão superficial. Verificou-se que a biodegradação do PCL é inibida pelos microrganismos do chorume adicionados no solo.Blend films of polycaprolactone (PCL and polypropylene (PP have been obtained by melt-pressing of both components. The biodegradation of PP/PCL blend films in soil and soil with leachate landfill has been assessed with measurements of evolution of CO2, weight loss, contact angle, scanning electronic microscopy (SEM and differential scanning calorimetry (DSC. The respirometric tests showed that the PP/PCL biodegradation in the soil with leachate was higher than the homopolymers, suggesting that the polymers in the blend are more susceptible to biodegradation owing to the lack of interaction between PP and PCL. The results also showed that biodegradation due to microorganisms in the soil with leachate occurred by surface erosion. It was found that the PCL biodegradation is inhibited by the leachate microorganisms added in the soil.

  4. A novel photoluminescent nanohybrid of poly(ε-caprolactone) grafted Mg/Al layered double hydroxides and Tb{sup 3+} ions: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Bach, Long Giang [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Center for Advanced Materials Research, Nguyen Tat Thanh Unviersity, Ho Chi Minh City (Viet Nam); Islam, Md. Rafiqul [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Energy and Mineral Resources Division, Ministry of Power, Energy and Mineral Resources, Government of the People’s Republic of Bangladesh, Dhaka 1000 (Bangladesh); Cao, Xuan Thang [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Park, Jong Myung [Surface Engineering Laboratory, Graduate Institute of Ferrous Technology, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Lim, Kwon Taek, E-mail: ktlim@pknu.ac.kr [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2014-01-05

    Highlights: • The photoluminescent LDHs-PCL-Tb{sup 3+} nanohybrid was successfully synthesized. • Structure and morphology of LDHs-g-PCL-Tb{sup 3+} were investigated by FT-IR, SEM, and TGA. • XPS and EDS analyses further suggested the formation of LDHs-g-PCL-Tb{sup 3+}. • Optical property of LDHs-g-PCL-Tb{sup 3+} was investigated by PL. -- Abstract: This paper demonstrates a systematic study of the synthesis and characterization of the hybrid of Mg–Al layer double hydroxides (LDHs), poly(ε-caprolactone) (PCL), and terbium ions (Tb{sup 3+}). The hybrid LDH-g-PCL-Tb{sup 3+}-1,10-phenanthroline (Phen) was prepared by the combination of ring opening polymerization (ROP), click chemistry, and coordination chemistry. First, LDHs with a molar ratio of Mg/Al = 2 were prepared by the co-precipitation method, which was subsequently functionalized with (3-chloropropyl) trimethoxysilane in order to introduce azide groups through the reaction of chlorine with sodium azide. Meanwhile, the acetylene functionalized PCL was prepared by ROP of ε-CL, followed by esterification of the hydroxyl groups using succinic anhydride. The click reaction of alkyne-PCL and N{sub 3}-LDHs successfully afforded LDH-g-PCL, which was coordinated with Tb{sup 3+} ions in the presence of Phen. The structure and properties of the nanohybrids were investigated by FT-IR, XPS, EDS, SEM, and TGA analyses. The data indicate the coordination of Tb{sup 3+} ions with LDH-g-PCL nanohybrids. The content of Tb{sup 3+} ions in the LDH-g-PCL-Tb{sup 3+}-Phen complex was calculated to be 8.7% (w/w). The LDH-g-PCL-Tb{sup 3+}-Phen complexes showed four emission bands with high fluorescence intensity centered at 489 nm ({sup 5}D{sub 4} → {sup 7}F{sub 6}), 546 nm ({sup 5}D{sub 4} → {sup 7}F{sub 5}), 586 nm ({sup 5}D{sub 4} → {sup 7}F{sub 4}) and 623 nm ({sup 5}D{sub 4} → {sup 7}F{sub 3}) with excitation at 328 nm ({sup 3}F{sub 6} → {sup 5}G{sub 6}). The stability of LDH-g-PCL-Tb{sup 3+}-Phen complexes

  5. Reverse logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); S.D.P. Flapper; R. Dekker (Rommert)

    2002-01-01

    textabstractThis paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In

  6. Electrospun fibers of layered double hydroxide/biopolymer nanocomposites as effective drug delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yue-E.; Zhu Hong; Chen Dan; Wang Ruiyu [State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Tjiu, Weng Weei [Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Liu Tianxi, E-mail: txliu@fudan.edu.cn [State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)

    2012-06-15

    Ibuprofen intercalated layered double hydroxide (LDH-IBU)/polycaprolactone (PCL) and LDH-IBU/polylactide (PLA) nanocomposite fibers are electrospun based on a combination of LDH-IBU with two kinds of biopolymers (i.e. PCL and PLA), to act as effective drug delivery systems. Ibuprofen (IBU) is chosen as a model drug, which is intercalated in MgAl-LDH by coprecipitation. Poly(oxyethylene-b-oxypropylene-b-oxyethylene) (Pluronic) is also added into PLA-based fibers as hydrophilicity enhancer and release modulator. LDH-IBU nanoparticles are uniformly dispersed throughout the nanocomposite fibers, as evidenced by transmission electron microscopy (TEM) observations. In vitro drug release studies show that initial IBU liberation from LDH-IBU/PCL composite fibers is remarkably slower than that from IBU/PCL fibers due to the sustained release property of LDH-IBU and heterogeneous nucleation effect of LDH-IBU on PCL chain segments. Surprisingly, the initial IBU release from LDH-IBU/PLA and LDH-IBU/PLA/Pluronic composite fibers is faster than that from the corresponding IBU/PLA and IBU/PLA/Pluronic fibers. This effect can be attributed to the strong interaction between alkyl groups in IBU molecules and methyl substituent groups of PLA as well as the hydrophilicity of LDH-IBU, which lead to an easier diffusion of water with a faster release of IBU from LDH-IBU/PLA and LDH-IBU/PLA/Pluronic composite fibers. - Graphical abstract: Ibuprofen intercalated layered double hydroxide (LDH-IBU)/polycaprolactone (PCL) and LDH-IBU/polylactide (PLA) nanocomposite fibers are electrospun based on the combination of LDHs with two kinds of biopolymers (i.e. PCL and PLA). LDH-IBU nanoparticles are uniformly dispersed throughout all the electrospun nanocomposite fibers even at a high loading level of 5 wt%. By combining the tunable drug release property of LDHs and electrospinning technique, the new drug delivery system is anticipated for effective loading and sustained release of drugs

  7. Reverse Osmosis

    Indian Academy of Sciences (India)

    ment of Civil Engineering and is presently the. Chairman of Center for. Sustainable Technologies,. Indian Institute of Science,. Bangalore. His research areas include, unsaturated soil behaviour, hazardous waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis,.

  8. Reverse Osmosis

    Indian Academy of Sciences (India)

    and is an Associate Faculty at Center for Sustainable. Technologies, Indian. Institute of Science,. Bangalore. His research areas include, unsaturated soil behaviour, hazardous waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis, desalinatiion, seawater, water.

  9. Reverse Osmosis

    Indian Academy of Sciences (India)

    /fulltext/reso/012/05/0037-0040. Keywords. Osmosis; reverse osmosis; desalinatiion; seawater; water purification. Author Affiliations. Sudhakar M Rao1. Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India.

  10. Reversible Sterilization

    Science.gov (United States)

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  11. Reduction of Fusarium wilt in watermelon by Pseudomonas chlororaphis PCL1391 and P. fluorescens WCS365

    Directory of Open Access Journals (Sweden)

    G.T. Tziros

    2007-12-01

    Full Text Available Fusarium wilt of watermelon (Citrullus lanatus caused by Fusarium oxysporum f. sp. niveum is a devastatine soil-borne disease that causes extensive losses throughout the world. Two known Pseudomonas biocontrol strains were used separately and in combination to assess their antagonistic effectiveness against F. oxysporum f. sp. niveum in pot experiments. P. chlororaphis PCL1391 signifi cantly reduced disease severity. P. fl uorescens WCS365 was less effective in disease suppression, while a combination of the two bacteria had intermediate effects. The biological control of Fusarium wilt with P. chlororaphis offers a potentially useful tool in an integrated pest management program to control Fusarium wilt of watermelon.

  12. A novel posteromedial approach for tibial inlay PCL reconstruction in KDIIIM injuries: avoiding prone patient positioning.

    Science.gov (United States)

    Richter, Dustin; Wascher, Daniel C; Schenck, Robert C

    2014-09-01

    Treatment of traumatic knee dislocations remains controversial and challenging. Current techniques for PCL reconstruction utilize either a transtibial approach with potential risk of vascular injury from drilling toward the popliteal artery or a tibial inlay technique with prone patient positioning, which is cumbersome and adds operative time. We therefore developed a surgical technique using a supine posteromedial approach for PCL tibial inlay reconstruction for the treatment of Schenck KDIIIM (ACL/PCL/medial collateral ligament) knee dislocations. In patients undergoing this technique, we evaluated patient-reported outcome scores, ROM, stability, and complications. Tibial inlay PCL reconstructions were performed through a posteromedial approach with the patient supine, knee flexed, and hip externally rotated, thus avoiding prone patient positioning. The inlay approach uses the interval between the medial head of the gastrocnemius and the pes anserinus (gracilis and semitendinosus), with release of the semimembranosus tendon approximately 1 cm from its insertion on the tibia. Retraction of the medial gastrocnemius and semimembranosus allows access to the posteromedial aspect of the proximal tibia while protecting the neurovascular bundle. All 11 patients sustaining a KDIIIM multiligamentous knee injury treated between 2002 and 2011 with a three-ligament reconstruction received this posteromedial approach. Seven patients were available for complete evaluation, and one completed telephone followup only. Mean followup was 6.0 years (range, 2.0-11.2 years). Clinical evaluation included Lysholm and Tegner activity scores and measurements of ROM and knee laxity. We also recorded complications. Mean Lysholm and Tegner activity scores were 81 and 4.9, respectively, with three patients returning to recreational or competitive sports. Mean knee flexion was 120° (range, 106°-137°); however, two patients had stiffness in flexion, lacking greater than 20° of flexion

  13. The Influence of the Polymer Amount on the Biological Properties of PCL/ZrO2 Hybrid Materials Synthesized via Sol-Gel Technique

    Directory of Open Access Journals (Sweden)

    Michelina Catauro

    2017-10-01

    Full Text Available Organic/inorganic hybrid materials are attracting considerable attention in the biomedical area. The sol-gel process provides a convenient way to produce many bioactive organic–inorganic hybrids. Among those, poly(e-caprolactone/zirconia (PCL/ZrO2 hybrids have proved to be bioactive with no toxic materials. The aim of this study was to investigate the effects of these materials on the cellular response as a function of the PCL content, in order to evaluate their potential use in the biomedical field. For this purpose, PCL/ZrO2 hybrids containing 6, 12, 24, and 50 wt % of PCL were synthesized by the sol-gel method. The effects of their presence on the NIH-3T3 fibroblast cell line carrying out direct cell number counting, MTT, cell damage assays, flow cytometry-based analysis of cell-cycle progression, and immunoblotting experiments. The results confirm and extend the findings that PCL/ZrO2 hybrids are free from toxicity. The hybrids containing 12 and 24 wt % PCL, (more than 6 and 50 wt % ones enhance cell proliferation when compared to pure ZrO2 by affecting cell cycle progression. The finding that the content of PCL in PCL/ZrO2 hybrids differently supports cell proliferation suggests that PCL/ZrO2 hybrids could be useful tools with different potential clinical applications.

  14. Photocatalytic antibacterial effect of ZnO nanoparticles into coaxial electrospun PCL fibers to prevent infections from skin injuries

    Science.gov (United States)

    Prado-Prone, G.; Silva-Bermúdez, P.; García-Macedo, J. A.; Almaguer-Flores, A.; Ibarra, C.; Velasquillo-Martínez, C.

    2017-02-01

    Antibacterial studies of inorganic nanoparticles (nps) have become important due to the increased bacterial resistance against antibiotics. We used Zinc oxide nanoparticles (ZnO nps), which possess excellent photocatalytic properties with a wide band gap (Eg), are listed as "generally recognized as safe" by the Food and Drug Administration (FDA) and have shown antibacterial activity (AA) against many bacterial strains. The AA of ZnO nps is partly attributed to the production of Reactive Oxygen Species (ROS) by photocatalysis. When ZnO nps in aqueous media are illuminated with an energy cell membrane damage resulting in cell death. However, the application of inorganic nps in medical treatments is limited due to the possible long-term side effects of nps release. To prevent its release, ZnO nps were dispersed into Polycaprolactone (PCL) fibers obtained by electrospinning technique. To optimize the use of ZnO nps concentration, we developed coreshell coaxial electrospun fibers where the core corresponded to PCL and the shell to a mixture of ZnO nps/PCL. Thus, ZnO nps were only dispersed on the surface of the fibers increasing its superficial contact area. We evaluated the AA against E. coli of different electrospun ZnO nps/PCL fibers under two different conditions: UVA pre-illumination and darkness. Preliminary results suggest that the AA against E. coli is better when electrospun ZnO nps/PCL were preilluminated with UVA than under darkness conditions.

  15. Scaffolds for bone tissue engineering fabricated from two different materials by the rapid prototyping technique: PCL versus PLGA.

    Science.gov (United States)

    Park, So Hee; Park, Dae Sung; Shin, Ji Won; Kang, Yun Gyeong; Kim, Hyung Keun; Yoon, Taek Rim; Shin, Jung-Woog

    2012-11-01

    Three dimensional tissue engineered scaffolds for the treatment of critical defect have been usually fabricated by salt leaching or gas forming technique. However, it is not easy for cells to penetrate the scaffolds due to the poor interconnectivity of pores. To overcome these current limitations we utilized a rapid prototyping (RP) technique for fabricating tissue engineered scaffolds to treat critical defects. The RP technique resulted in the uniform distribution and systematic connection of pores, which enabled cells to penetrate the scaffold. Two kinds of materials were used. They were poly(ε-caprolactone) (PCL) and poly(D, L-lactic-glycolic acid) (PLGA), where PCL is known to have longer degradation time than PLGA. In vitro tests supported the biocompatibility of the scaffolds. A 12-week animal study involving various examinations of rabbit tibias such as micro-CT and staining showed that both PCL and PLGA resulted in successful bone regeneration. As expected, PLGA degraded faster than PCL, and consequently the tissues generated in the PLGA group were less dense than those in the PCL group. We concluded that slower degradation is preferable in bone tissue engineering, especially when treating critical defects, as mechanical support is needed until full regeneration has occurred.

  16. The Psychopathy Checklist-Revised (PCL-R), low anxiety, and fearlessness: a structural equation modeling analysis.

    Science.gov (United States)

    Neumann, Craig S; Johansson, Peter T; Hare, Robert D

    2013-04-01

    The current study employed a large representative sample of violent male offenders within the Swedish prison system to examine the factor structure of the PCL-R and the latent variable relations between the PCL-R items and clinical ratings of low trait anxiety and trait fearlessness (LAF). Consistent with previous research, confirmatory factor analysis (CFA) revealed strong support for the four-factor model of psychopathy (Interpersonal, Affective, Lifestyle, and Antisocial). Also, a series of CFAs revealed that the LAF items could be placed on any of the PCL-R factors without any changes in model fit. Finally, structural equation modeling results indicated that a PCL-R superordinate factor was able to account for most of the variance of a separate LAF factor. Taken together, the results indicate that if low anxiety and fearlessness, as measured via clinical ratings, are part of the psychopathy construct they are comprehensively accounted for by extant PCL-R items. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  17. Nanofiber Alignment Regulates NIH3T3 Cell Orientation and Cytoskeletal Gene Expression on Electrospun PCL+Gelatin Nanofibers.

    Science.gov (United States)

    Fee, Timothy; Surianarayanan, Swetha; Downs, Crawford; Zhou, Yong; Berry, Joel

    2016-01-01

    To examine the influence of substrate topology on the behavior of fibroblasts, tissue engineering scaffolds were electrospun from polycaprolactone (PCL) and a blend of PCL and gelatin (PCL+Gel) to produce matrices with both random and aligned nanofibrous orientations. The addition of gelatin to the scaffold was shown to increase the hydrophilicity of the PCL matrix and to increase the proliferation of NIH3T3 cells compared to scaffolds of PCL alone. The orientation of nanofibers within the matrix did not have an effect on the proliferation of adherent cells, but cells on aligned substrates were shown to elongate and align parallel to the direction of substrate fiber alignment. A microarray of cyotoskeleton regulators was probed to examine differences in gene expression between cells grown on an aligned and randomly oriented substrates. It was found that transcriptional expression of eight genes was statistically different between the two conditions, with all of them being upregulated in the aligned condition. The proteins encoded by these genes are linked to production and polymerization of actin microfilaments, as well as focal adhesion assembly. Taken together, the data indicates NIH3T3 fibroblasts on aligned substrates align themselves parallel with their substrate and increase production of actin and focal adhesion related genes.

  18. Reduction of Electromagnetic Interference Using ZnO-PCL Nanocomposites at Microwave Frequency

    Directory of Open Access Journals (Sweden)

    Abubakar Yakubu

    2015-01-01

    Full Text Available In industrial equipment and home appliance applications, the electromagnetic compatibility compliance directive (ECCD demands that electromagnetic interference side effects be eliminated or marginally minimized. The equipment must not disturb radio and telecommunication as well as other appliances. Additionally the ECCD also governs the immunity of such equipment to interference and seeks to ensure that this equipment is not disturbed by radio emissions when used as intended. Many types of absorbing materials are commercially available. However, many are expensive and not environmentally friendly. It is in the light of the above that we studied the electromagnetic absorption properties of ZnO-PCL nanocomposites prepared from cheap and abundant resources which are environmentally friendly (zinc and polycaprolactone. The test was carried out using a microstrip, open ended coaxial probe, and vector network analyzer. Amongst other findings, result showed that the ZnO-PCL nanocomposite has the capability of attenuating microwave frequency up to −18.2 dB due to their very high specific surface areas attributed to the nanofillers at 12 GHz.

  19. Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL

    Directory of Open Access Journals (Sweden)

    Julia Matena

    2015-06-01

    Full Text Available Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL, intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating.

  20. Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL

    Science.gov (United States)

    Matena, Julia; Petersen, Svea; Gieseke, Matthias; Teske, Michael; Beyerbach, Martin; Kampmann, Andreas; Escobar, Hugo Murua; Gellrich, Nils-Claudius; Haferkamp, Heinz; Nolte, Ingo

    2015-01-01

    Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL), intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM) process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating. PMID:26068455

  1. Surface modification of Ti-30Ta alloy by electrospun PCL deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wada, C.M.; Rangel, A.L.R.; Souza, M.A. de; Claro, A.P.R.A.; Rezende, M.C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil); Almeida, R. dos S. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2014-07-01

    Full text: Surface modifications techniques have been used for change the inert surface of the titanium alloys for better interaction. Ingots of the experimental alloy Ti30Ta were melted in an arc furnace and re-melted ten times at least. They were homogenized under vacuum at 1000 °C for 86. 4 ks to eliminate chemical segregation and cold-worked by swaging. Discs were immersed in aqueous NaOH solution for 24 h, dried at room temperature, immersed in HCl and dried at 40 °C in oven for 24 hours. Followed, PCL fibers were deposited on the Ti30Ta alloy discs surfaces by electrospinning. Plasma treatment was carried out for change PCL electrospun by using stainless steel plasma reactor. Samples were immersed in SBF 5x solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and SBF immersion. Results are very interesting for biomedical applications. (author)

  2. TiO2/PCL hybrid materials synthesized via sol-gel technique for biomedical applications.

    Science.gov (United States)

    Catauro, M; Bollino, F; Papale, F; Marciano, S; Pacifico, S

    2015-02-01

    The aim of the present work has been the synthesis of organic/inorganic hybrid materials based on titanium dioxide and poly(ε-caprolactone) (PCL) to be used in the biomedical field. Several materials have been synthesized using sol-gel methods by adding different amounts of polymer to the inorganic sol. The obtained gels have been characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The FT-IR data allowed us to hypothesize that the structure formed was that of an interpenetrating network, realized by hydrogen bonds between TiOH groups in the sol-gel intermediate species and carbonyl groups in the polymer repeating units. SEM and AFM analyses highlighted that the obtained materials were nanostructurated hybrids. To evaluate the biological properties of the hybrids, their bioactivity and cytotoxicity were investigated as a function of the PCL amount. The bioactivity of the synthesized systems was proven by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating human blood plasma (SBF). MTT cytotoxicity tests and Trypan Blue dye exclusion tests were carried out exposing NIH-3T3 mouse embryonic fibroblasts for 24 and 48h to extracts from the investigated hybrid materials. The results showed that all the hybrids had a non-cytotoxic effect on target cells. Copyright © 2014. Published by Elsevier B.V.

  3. Relationships between mechanical properties and drug release from electrospun fibers of PCL and PLGA blends.

    Science.gov (United States)

    Chou, Shih-Feng; Woodrow, Kim A

    2017-01-01

    Electrospun nanofibers have the potential to achieve high drug loading and the ability to sustain drug release. Mechanical properties of the drug-incorporated fibers suggest the importance of drug-polymer interactions. In this study, we investigated the mechanical properties of electrospun polycaprolactone (PCL) and poly (D,L-lactic-co-glycolic) acid (PLGA) fibers at various blend ratios in the presence and absence of a small molecule hydrophilic drug, tenofovir (TFV). Young׳s modulus of the blend fibers showed dependence on PLGA content and the addition of the drug. At a PCL/PLGA (20/80) composition, Young׳s modulus and tensile strength were independent of drug loading up to 40wt% due to offsetting effects from drug-polymer interactions. In vitro drug release studies suggested that release of TFV significantly decreased fiber mechanical properties. In addition, mechanically stretched fibers displayed a faster release rate as compared to the non-stretched fibers. Finally, drug partition in the blend fibers was estimated using a mechanical model and then experimentally confirmed with a composite of individually stacked fiber meshes. This work provides scientific understanding on the dependence of drug release and drug loading on the mechanical properties of drug-eluting fibers. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. PCL/PLA Polymer Composite Filament Fabrication using Full Factorial Design (DOE) for Fused Deposition Modelling

    Science.gov (United States)

    Haq, R. H. A.; Khairilhijra, K. Rd.; Wahab, M. S.; Sa’ude, N.; Ibrahim, M.; Marwah, O. M. F.; Yusof, M. S.; Rahman, M. N. A.; Ariffin, A. M. T.; Hassan, M. F.; Yunos, M. Z.; Adzila, S.

    2017-10-01

    In this study, Polycaprolactone / Polylactice Acid (PCL/PLA) composite are used to fabricate filament wire with the specific diameter, which is in the range of 1.75 to 1.80 mm. Full factorial experimental design technique was used to study the main effects and the interaction effects between operational parameter which is (A) die temperature, (B) roller puller speed, (C) spindle speed and (D) inlet temperature. Besides that, there are two levels (-1 and +1) and the response are filament wire diameter. There are 16 numbers of runs and plus 8 centre points per blocks which makes the runs into 24 runs. From the experiment it shows that there are four factor that are significant effects on the filament wire diameter which is A, B, C and BC. The optimum parameter setting are also determined and there are 10 suggestions to achieve the target with different setting of parameter. The margin error for confirmation run is below than 15% when the parameter set at 6 Hz spindle speed, 4.99 rpm roller puller, 100.31 °C die temperature and 79.65 °C inlet temperature which can be noted that the confirmation run result is acceptable. The optimization parameter setting can use to continue in Fused Deposition Modelling (FDM). Filament wire from PCL/PLA are succesfully fabricated with acceptable diameter size and ready to be used for Fused Depotion Modelling process (FDM).

  5. PCL tibial avulsion with an associated medial meniscal tear in a child: a case report on diagnosis and management.

    LENUS (Irish Health Repository)

    2012-02-01

    Posterior cruciate ligament (PCL) injuries from tibial avulsions are rare in the paediatric setting. One would need a high index of suspicion as clinical examination may be difficult, especially in the early period. Magnetic resonance imaging is an excellent diagnostic modality for this condition and other associated injuries within the knee. We report a rare case in which the patient had a PCL avulsion off the tibial insertion site with an associated posterior horn medial meniscal tear off the posterior capsule. He was treated through open reduction and internal fixation of the avulsed fragment with suture repair of the meniscal tear. We emphasize the importance of diagnosing and managing associated intra-articular injuries when dealing with the rare condition of PCL tibial avulsion in the paediatric setting.

  6. Reverse mortgages.

    Science.gov (United States)

    Farnesi, D

    1995-09-01

    Elders and their families are often caught in a financial bind when it comes to paying for much-needed home care services. Reverse mortgages may offer a solution to elderly home care clients who own their homes but have a limited income with which to maintain their independence.

  7. Reversible Computing

    Science.gov (United States)

    1980-02-01

    will have been introduced. 9. Reversible celular autemata We shall assume the reader to have some familiarity with the concept of cel- lular...10003 Mr. Kin B. Thcmpson 1 copy Technical Director Information Systems Divisia.i Naval Research Laboratory (OP-91T) Technical Information Division

  8. Surface modification of PCL-TCP scaffolds improve interfacial mechanical interlock and enhance early bone formation : An in vitro and in vivo characterization

    NARCIS (Netherlands)

    Yeo, A.; Wong, W. J.; Khoo, H. H.; Teoh, S. H.

    Pretreatment of polycaprolactone-20% tricalcium phosphate (PCL-TCP) scaffolds under alkaline conditions can be utilized to alter surface characteristics for enhanced early bone formation. PCL-TCP scaffolds were treated with sodium hydroxide (NaOH) at various time intervals (group A: untreated, group

  9. Enhanced corrosion resistance and biocompatibility of AZ31 Mg alloy using PCL/ZnO NPs via electrospinning

    Science.gov (United States)

    Kim, Jinwoo; Mousa, Hamouda M.; Park, Chan Hee; Kim, Cheol Sang

    2017-02-01

    In the efforts to improve corrosion resistance and biocompatibility of magnesium alloys, polycarprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs) composite coatings were applied onto AZ31 Mg alloys via electrospinning technique in this study. The PCL/ZnO composite coatings on Mg alloys were characterized by using FE-SEM, EDX, XPS, and FT-IR. Moreover, coating adhesion test, electrochemical corrosion test, and biocompatibility test in vitro were performed to measure coating performance. Our results revealed that the increase in the content of ZnO NPs in the composite coatings not only improved the coating adhesion of composite coatings on Mg alloys, but also increased the corrosion resistance. Furthermore, the biocompatibility of MC3T3-E1 osteoblasts of the PCL/ZnO composite coated samples was superior to the biocompatibility of the bare samples. Such data suggest that applying PCL/ZnO composite coating to the magnesium alloys has suitable potential in biomedical applications.

  10. When experts disagreed, who was correct? A comparison of PCL-R scores from independent raters and opposing forensic experts.

    Science.gov (United States)

    Rufino, Katrina A; Boccaccini, Marcus T; Hawes, Samuel W; Murrie, Daniel C

    2012-12-01

    Researchers recently found that Psychopathy Checklist-Revised (PCL-R; Hare, 2003) scores reported by state experts were much higher than those reported by defense experts in sexually violent predator cases pursued for civil commitment (Murrie, Boccaccini, Johnson, & Janke, 2008), which raised the question of which scores were more accurate. In this study, two independent raters rescored the PCL-R from file review for 44 offenders from that sample who had opposing evaluator scores (allegiance cases) and 44 who had state expert, but not defense expert, scores (comparison cases). The independent raters agreed with one another in their scoring of the allegiance and comparison cases (Intraclass Correlation Coefficient [ICC] ICCA,1 = .95), but they disagreed with both state (ICCA,1 = .29) and defense (ICCA,1 = .14) experts in the allegiance cases. Agreement was stronger between state experts and independent raters for the comparison cases (ICCA,1 = .63), but the independent raters assigned significantly higher PCL-R scores than experts for both the allegiance and comparison cases. These findings suggest that offenders who were selected for rescoring by the defense may have been more difficult to score. Findings also raise questions about the extent to which PCL-R scores based on correctional file review only are comparable to those based on file and interview.

  11. 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.

  12. A Multimethod Assessment of Juvenile Psychopathy: Comparing the Predictive Utility of the PCL:YV, YPI, and NEO PRI

    Science.gov (United States)

    Cauffman, Elizabeth; Kimonis, Eva R.; Dmitrieva, Julia; Monahan, Kathryn C.

    2009-01-01

    The current study compares 3 distinct approaches for measuring juvenile psychopathy and their utility for predicting short- and long-term recidivism among a sample of 1,170 serious male juvenile offenders. The assessment approaches compared a clinical interview method (the Psychopathy Checklist: Youth Version [PCL:YV]; Forth, Kosson, & Hare,…

  13. Using the PCL-R to Help Estimate the Validity of Two Self-Report Measures of Psychopathy with Offenders

    Science.gov (United States)

    Poythress, Norman G.; Lilienfeld, Scott O.; Skeem, Jennifer L.; Douglas, Kevin S.; Edens, John F.; Epstein, Monica; Patrick, Christopher J.

    2010-01-01

    Two self-report measures of psychopathy, Levenson's Primary and Secondary Psychopathy scales (LPSP) and the Psychopathic Personality Inventory (PPI), were administered to a large sample of 1,603 offenders. The most widely researched measure of criminal psychopathy, the Hare Psychopathy Checklist-Revised (PCL-R), served as a provisional referent…

  14. In vitro and in vivo evaluation of electrospun nanofibers of PCL, chitosan and gelatin: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, S.R., E-mail: srrg@campus.fct.unl.pt [Centro de Física e Investigação Tecnológica/Departamento de Física Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Rodrigues, G. [Centro de Biologia Ambiental/Departamento de Biologia Animal Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Martins, G.G. [Centro de Biologia Ambiental/Departamento de Biologia Animal Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Instituto Gulbenkian de Ciência, R. da Quinta Grande, 6, 2780-156 Oeiras (Portugal); Roberto, M.A. [Departamento de Cirurgia Plástica e Reconstrutiva e Unidade de Queimados, Hospital de São José, Rua José António Serrano, 1150-199 Lisboa (Portugal); Mafra, M. [Serviço de Anatomia Patológica, Hospital de São José, Rua José António Serrano, 1150-199 Lisboa (Portugal); Henriques, C.M.R. [Centro de Física e Investigação Tecnológica/Departamento de Física Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); and others

    2015-01-01

    Many polymers have been investigated with respect to their use in skin tissue engineering. However, directly comparable data on the role played by different polymers in assisting skin wound healing requires their in vitro and in vivo evaluation under the same conditions. Therefore, we performed a study in order to compare the performance of electrospun nanofiber mats from three different polymers concerning cell–scaffold interaction and wound healing promotion. A polyester (polycaprolactone, PCL), a protein (gelatin from cold water fish skin, GEL) and a polysaccharide (chitosan, CS) were the polymers chosen. Gelatin nanofibers were crosslinked with glutaraldehyde vapor. The scaffolds were characterized physico-chemically, in vitro by seeding with human fetal fibroblasts, HFFF2, and used in vivo as skin substitutes in a rat wound model with total skin removal. In vitro tests revealed that cells adhered and proliferated in all scaffolds. However, cells deep into the scaffold were only observed in the PCL and CS scaffolds. In in vivo tests CS scaffolds had the highest impact on the healing process by decreasing the extent of wound contraction and enhancing the production of a neodermis and re-epithelialization of the wound. - Highlights: • We produced and compared the properties of electrospun PCL, CS and fish GEL. • In vitro, cells adhered and proliferated better on GEL scaffolds. • Deep cell migration was observed in the PCL and CS matrices. • In vivo, both CS and GEL matrices integrated well within the wounds. • Only CS effectively blocked, although only partially, the contraction phenomenon.

  15. Surface modification of MPEG-b-PCL-based nanoparticles via oxidative self-polymerization of dopamine for malignant melanoma therapy

    Science.gov (United States)

    Xiong, Wei; Peng, Lixia; Chen, Hongbo; Li, Qin

    2015-01-01

    To enhance the therapeutic effects of chemotherapy on malignant melanoma, paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) nanoparticles (MPEG-b-PCL NPs) that had their surfaces modified with polydopamine (PTX-loaded MPEG-b-PCL NPs@PDA) were prepared as drug vehicles. The block copolymer MPEG-b-PCL was synthesized by ring-opening polymerization and characterized by proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The PTX-loaded NPs were prepared by a modified nanoprecipitation technique. The PTX-loaded NPs and PTX-loaded NPs@PDA were characterized in terms of size and size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin-6-loaded NPs@PDA could be internalized by human melanoma cell line A875 cells. The cellular uptake efficiency of NPs was greatly enhanced after PDA modification. The antitumor efficacy of the PTX-loaded NPs@PDA was investigated in vitro by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and in vivo by a xenograft tumor model. The PTX-loaded NPs@PDA could significantly inhibit tumor growth compared to Taxol® and precursor PTX-loaded NPs. All the results suggested that the PTX-loaded MPEG-b-PCL NPs that had their surfaces modified with PDA are promising nanocarriers for malignant melanoma therapy. PMID:25945046

  16. In-vivo characterization of a 3D hybrid scaffold based on PCL/decellularized aorta for tracheal tissue engineering.

    Science.gov (United States)

    Ghorbani, Fariba; Moradi, Lida; Shadmehr, Mohammad Behgam; Bonakdar, Shahin; Droodinia, Atosa; Safshekan, Farzaneh

    2017-12-01

    As common treatments for long tracheal stenosis are associated with several limitations, tracheal tissue engineering is considered as an alternative treatment. This study aimed at preparing a hybrid scaffold, based on biologic and synthetic materials for tracheal tissue engineering. Three electrospun polycaprolactone (PCL) scaffolds, namely E1 (pure PCL), E2 (collagen-coated PCL) and E3 (PCL blended with collagen) were prepared. Allogeneic aorta was harvested and decellularized. A biodegradable PCL stent was fabricated and inserted into the aorta to prevent its collapse. Scaffold characterization results revealed that the 2-h swelling ratio of E2 was significantly higher than those of E1 and E3. In the first 3months, E2 and E3 exhibited almost equal degradabilities (significantly higher than that of E1). Moreover, tensile strengths of all samples were comparable with those of human trachea. Using rabbit's adipose-derived mesenchymal stem cells (AMSCs) and primary chondrocytes, E3 exhibited the highest levels of GAG release within 21days as well as collagen II and aggrecan expression. Fot the next step, AMSC-chondrocyte co-culture seeded scaffold was sutured to the acellular aorta, implanted into rabbits' muscle, and finally harvested after 4weeks of follow up. Harvested structures were totally viable due to the angiogenesis created by the muscle. H&E and alcian blue staining results revealed the presence of chondrocytes in the structure and GAG in the produced extracellular matrix. Since tracheal replacement using biologic and synthetic scaffolds usually results in tracheal collapse or granulation formation, a hybrid construct may provide the required rigidity and biocompatibility for the substitute. Copyright © 2017. Published by Elsevier B.V.

  17. Comparative Efficacies of a 3D-Printed PCL/PLGA/β-TCP Membrane and a Titanium Membrane for Guided Bone Regeneration in Beagle Dogs

    Directory of Open Access Journals (Sweden)

    Jin-Hyung Shim

    2015-10-01

    Full Text Available This study was conducted to evaluate the effects of a 3D-printed resorbable polycaprolactone/poly(lactic-co-glycolic acid/β-tricalcium phosphate (PCL/PLGA/β-TCP membrane on bone regeneration and osseointegration in areas surrounding implants and to compare results with those of a non-resorbable titanium mesh membrane. After preparation of PCL/PLGA/β-TCP membranes using extrusion-based 3D printing technology; mechanical tensile testing and in vitro cell proliferation testing were performed. Implant surgery and guided bone regeneration were performed randomly in three groups (a no membrane group, a titanium membrane group, and a PCL/PLGA/β-TCP membrane group (n = 8 per group. Histological and histometric analyses were conducted to evaluate effects on bone regeneration and osseointegration. Using the results of mechanical testing; a PCL/PLGA/β-TCP ratio of 2:6:2 was selected. The new bone areas (% in buccal defects around implants were highest in the PCL/PLGA/β-TCP group and significantly higher than in the control group (p < 0.05. Bone-to-implant contact ratios (% were also significantly higher in the PCL/PLGA/β-TCP and titanium groups than in the control group (p < 0.05. When the guided bone regeneration procedure was performed using the PCL/PLGA/β-TCP membrane; new bone formation around the implant and osseointegration were not inferior to those of the non-resorbable pre-formed titanium mesh membrane.

  18. Comparative Efficacies of Collagen-Based 3D Printed PCL/PLGA/β-TCP Composite Block Bone Grafts and Biphasic Calcium Phosphate Bone Substitute for Bone Regeneration.

    Science.gov (United States)

    Hwang, Kyoung-Sub; Choi, Jae-Won; Kim, Jae-Hun; Chung, Ho Yun; Jin, Songwan; Shim, Jin-Hyung; Yun, Won-Soo; Jeong, Chang-Mo; Huh, Jung-Bo

    2017-04-17

    The purpose of this study was to compare bone regeneration and space maintaining ability of three-dimensional (3D) printed bone grafts with conventional biphasic calcium phosphate (BCP). After mixing polycaprolactone (PCL), poly (lactic-co-glycolic acid) (PLGA), and β-tricalcium phosphate (β-TCP) in a 4:4:2 ratio, PCL/PLGA/β-TCP particulate bone grafts were fabricated using 3D printing technology. Fabricated particulate bone grafts were mixed with atelocollagen to produce collagen-based PCL/PLGA/β-TCP composite block bone grafts. After formation of calvarial defects 8 mm in diameter, PCL/PLGA/β-TCP composite block bone grafts and BCP were implanted into bone defects of 32 rats. Although PCL/PLGA/β-TCP composite block bone grafts were not superior in bone regeneration ability compared to BCP, the results showed relatively similar performance. Furthermore, PCL/PLGA/β-TCP composite block bone grafts showed better ability to maintain bone defects and to support barrier membranes than BCP. Therefore, within the limitations of this study, PCL/PLGA/β-TCP composite block bone grafts could be considered as an alternative to synthetic bone grafts available for clinical use.

  19. Predicting violent infractions in a Swiss state penitentiary: a replication study of the PCL-R in a population of sex and violent offenders.

    Science.gov (United States)

    Endrass, Jérôme; Rossegger, Astrid; Urbaniok, Frank; Laubacher, Arja; Vetter, Stefan

    2008-09-08

    Research conducted with forensic psychiatric patients found moderate correlations between violence in institutions and psychopathy. It is unclear though, whether the PCL-R is an accurate instrument for predicting aggressive behavior in prisons. Results seem to indicate that the instrument is better suited for predicting verbal rather than physical aggression of prison inmates. PCL-R scores were assessed for a sample of 113 imprisoned sex and violent offenders in Switzerland. Logistic regression analyses were used to estimate physical and verbal aggression as a function of the PCL-R sum score. Additionally, stratified analyses were conducted for Factor 1 and 2. Infractions were analyzed as to their motives and consequences. The mean score of the PCL-R was 12 points. Neither the relationship between physical aggression and the sum score of the PCL-R, nor the relationship between physical aggression and either of the two factors of the PCL-R were significant. Both the sum score and Factor 1 predicted the occurrence of verbal aggression (AUC=0.70 and 0.69), while Factor 2 did not. Possible explanations are discussed for the weak relationship between PCL-R scores and physically aggressive behavior during imprisonment. Some authors have discussed whether the low base rate of violent infractions can be considered an explanation for the non-significant relation between PCL-R-score and violence. The base rate in this study, however, with 27%, was not low. It is proposed that the distinction between reactive and instrumental motives of institutional violence must be considered when examining the usefulness of the PCL-R in predicting in-prison physical aggressive behavior.

  20. Predicting violent infractions in a Swiss state penitentiary: A replication study of the PCL-R in a population of sex and violent offenders

    Directory of Open Access Journals (Sweden)

    Laubacher Arja

    2008-09-01

    Full Text Available Abstract Background Research conducted with forensic psychiatric patients found moderate correlations between violence in institutions and psychopathy. It is unclear though, whether the PCL-R is an accurate instrument for predicting aggressive behavior in prisons. Results seem to indicate that the instrument is better suited for predicting verbal rather than physical aggression of prison inmates. Methods PCL-R scores were assessed for a sample of 113 imprisoned sex and violent offenders in Switzerland. Logistic regression analyses were used to estimate physical and verbal aggression as a function of the PCL-R sum score. Additionally, stratified analyses were conducted for Factor 1 and 2. Infractions were analyzed as to their motives and consequences. Results The mean score of the PCL-R was 12 points. Neither the relationship between physical aggression and the sum score of the PCL-R, nor the relationship between physical aggression and either of the two factors of the PCL-R were significant. Both the sum score and Factor 1 predicted the occurrence of verbal aggression (AUC = 0.70 and 0.69, while Factor 2 did not. Conclusion Possible explanations are discussed for the weak relationship between PCL-R scores and physically aggressive behavior during imprisonment. Some authors have discussed whether the low base rate of violent infractions can be considered an explanation for the non-significant relation between PCL-R-score and violence. The base rate in this study, however, with 27%, was not low. It is proposed that the distinction between reactive and instrumental motives of institutional violence must be considered when examining the usefulness of the PCL-R in predicting in-prison physical aggressive behavior.

  1. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  2. In Vitro Evaluation of PCL and P(3HB as Coating Materials for Selective Laser Melted Porous Titanium Implants

    Directory of Open Access Journals (Sweden)

    Michael Grau

    2017-11-01

    Full Text Available Titanium is widely used as a bone implant material due to its biocompatibility and high resilience. Since its Young’s modulus differs from bone tissue, the resulting “stress shielding” could lead to scaffold loosening. However, by using a scaffold-shaped geometry, the Young’s modulus can be adjusted. Also, a porous geometry enables vascularisation and bone ingrowth inside the implant itself. Additionally, growth factors can improve these effects. In order to create a deposit and release system for these factors, the titanium scaffolds could be coated with degradable polymers. Therefore, in the present study, synthetic poly-ε-caprolactone (PCL and the biopolymer poly(3-hydroxybutyrate (P(3HB were tested for coating efficiency, cell adhesion, and biocompatibility to find a suitable coating material. The underlying scaffold was created from titanium by Selective Laser Melting (SLM and coated with PCL or P(3HB via dip coating. To test the biocompatibility, Live Cell Imaging (LCI as well as vitality and proliferation assays were performed. In addition, cell adhesion forces were detected via Single Cell Force Spectroscopy, while the coating efficiency was observed using environmental scanning electron microscopy (ESEM and energy-dispersive X-ray (EDX analyses. Regarding the coating efficiency, PCL showed higher values in comparison to P(3HB. Vitality assays revealed decent vitality values for both polymers, while values for PCL were significantly lower than those for blank titanium. No significant differences could be observed between PCL and P(3HB in proliferation and cell adhesion studies. Although LCI observations revealed decreasing values in cell number and populated area over time on both polymer-coated scaffolds, these outcomes could be explained by the possibility of coating diluent residues accumulating in the culture medium. Overall, both polymers fulfill the requirements regarding biocompatibility. Nonetheless, since only PCL

  3. Mussel-inspired functionalization of PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Tian, Peng; Xu, Demin; Liu, Xuanyong

    2016-05-01

    The rapid degradation of magnesium-based implants in physiological environments in vivo not only will quickly deteriorate their mechanical strengths but will also lead to a severe change of the micro-environment around the implants, which may cause the final failure of magnesium-based implants. In this work, a polycaprolactone (PCL) layer was prepared to seal the plasma electrolytic oxidization coating (PEO) to form a PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy, followed by further surface functionalization with polydopamine. The in vitro degradation behaviors of the bare AZ31 alloy and coated samples were evaluated in a simulated body fluid (SBF) using the potentiodynamic polarization curve test and the static immersion test. The bioactivity of the samples was investigated using the SBF soaking test. The cytocompatibility of all samples was evaluated using the cytotoxicity test and analysis of the adhesion and proliferation of osteoblast cells (MC3T3-E1) directly cultivated on the sample surface. The results showed that the PCL layer successfully sealed the pores of the PEO coating, and then the polydopamine layer formed on its surface. The in vitro degradation tests showed that the PEO/PCL composite coating improved the corrosion resistance of the AZ31 alloy in SBF with a more positive corrosion potential and a lower corrosion current density. Due to the protection of the PEO/PCL composite coating, the surrounding environment showed nearly no influence on the degradation of the coated sample, which led to no obvious local alkalization and hydrogen evolution. Moreover, compared with the AZ31 alloy and PEO coating, the PEO/PCL composite coating was more suitable for cell adhesion and proliferation. After further surface functionalization by polydopamine, the corrosion resistance of the composite coating was maintained, while its bioactivity was significantly enhanced with a large amount of hydroxyapatite (HA) formed on its surface after

  4. Chronic caffeine treatment reverses memory impairment and the expression of brain BNDF and TrkB in the PS1/APP double transgenic mouse model of Alzheimer?s disease

    OpenAIRE

    HAN, KUN; JIA, NING; LI, JI; YANG, LI; MIN, LIAN-QIU

    2013-01-01

    The objective of this study was to investigate the effects of varying doses of caffeine on memory impairment and the expression of brain neurotrophic derived factor (BNDF) and TrkB in PS1/APP double transgenic mouse models. PS1/APP double transgenic mice were administered 0.3 ml/day of saline, 1.5 mg/day of caffeine or 0.75 mg/day of caffeine for eight weeks. A water maze test and western blotting were used to determine the memory capability and expression of hippocampal BNDF and TrkB of the ...

  5. Behaviour of human mesenchymal stem cells on chemically synthesized HA-PCL scaffolds for hard tissue regeneration.

    Science.gov (United States)

    D'Antò, Vincenzo; Raucci, Maria Grazia; Guarino, Vincenzo; Martina, Stefano; Valletta, Rosa; Ambrosio, Luigi

    2016-02-01

    Our goal was to characterize the response of human mesenchymal stem cells (hMSCs) to a novel composite scaffold for bone tissue engineering. The hydroxyapatite-polycaprolactone (HA-PCL) composite scaffolds were prepared by a sol-gel method at room temperature and the scaffold morphology was investigated by scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) to validate the synthesis process. The response of two different lines of hMSCs, bone-marrow-derived human mesenchymal stem cells (BMSCs) and dental pulp stem cells (DPSCs) in terms of cell proliferation and differentiation into the osteoblastic phenotype, was evaluated using Alamar blue assay, SEM, histology and alkaline phosphatase activity. Our results indicate that tissue engineering by means of composite HA-PCL scaffolds may represent a new therapeutic strategy to repair craniofacial bone defects. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Experimental research of ZrO{sub 2}/BCP/PCL scaffold with complex pore pattern for bone tissue

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Min Woo; Shin, Hae Ri; Kim, Jong Young [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of)

    2015-11-15

    Recently, synthetic biopolymers and bioceramics such as poly (-caprolactone)(PCL), hydroxyapatite, tricalcium phosphate, biphasic calcium phosphate(BCP), and zirconia have been used as substrates to generate various tissues or organs in tissue engineering. Thus, the purpose of this study was the characterization of ZrO{sub 2}/BCP/PCL(ZBP) scaffold for bone tissue regeneration. Based on the result of single-line test, blended 3D ZBP scaffolds with fully interconnected pores and new complex pore pattern of -type and staggered-type were successfully fabricated using a polymer deposition system. Furthermore, the effect of ZBP scaffold on mechanical property was analyzed. In addition, in vitro cell interaction of ZBP scaffold on MG63 cells was evaluated using a cell counting kit-8(CCK-8) assay.

  7. Evaluation of Electrospun PCL-PIBMD Meshes Modified with Plasmid Complexes in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Yakai Feng

    2016-02-01

    Full Text Available Functional artificial vascular meshes from biodegradable polymers have been widely explored for certain tissue engineered meshes. Still, the foreign body reaction and limitation in endothelialization are challenges for such devices. Here, degradable meshes from phase-segregated multiblock copolymers consisting of poly(ε-caprolactone (PCL and polydepsipeptide segments are successfully prepared by electrospinning and electrospraying techniques. The pEGFP-ZNF580 plasmid microparticles (MPs-pZNF580 were loaded into the electrospun meshes to enhance endothelialization. These functional meshes were evaluated in vitro and in vivo. The adhesion and proliferation of endothelial cells on the meshes were enhanced in loaded mesh groups. Moreover, the hemocompatibility and the tissue response of the meshes were further tested. The complete tests showed that the vascular meshes modified with MPs-pZNF580 possessed satisfactory performance with an average fiber diameter of 550 ± 160 nm, tensile strength of 27 ± 3 MPa, Young’s modulus of 1. 9 ± 0.2 MPa, water contact angle of 95° ± 2°, relative cell number of 122% ± 1% after 7 days of culture, and low blood platelet adhesion as well as weak inflammatory reactions compared to control groups.

  8. Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold

    Science.gov (United States)

    Nail, Lindsay N.; Zhang, Dawei; Reinhard, Jessica L.; Grunlan, Melissa A.

    2015-01-01

    Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to the success of this approach is a scaffold that is able to conformally fit within an irregular defect while also having the requisite biodegradability, pore interconnectivity and bioactivity. By nature of their shape recovery and fixity properties, shape memory polymer (SMP) scaffolds could achieve defect “self-fitting.” In this way, following exposure to warm saline (~60 ºC), the SMP scaffold would become malleable, permitting it to be hand-pressed into an irregular defect. Subsequent cooling (~37 ºC) would return the scaffold to its relatively rigid state within the defect. To meet these requirements, this protocol describes the preparation of SMP scaffolds prepared via the photochemical cure of biodegradable polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method. A fused salt template is utilized to achieve pore interconnectivity. To realize bioactivity, a polydopamine coating is applied to the surface of the scaffold pore walls. Characterization of self-fitting and shape memory behaviors, pore interconnectivity and in vitro bioactivity are also described. PMID:26556112

  9. Effect of halloysite on structure and properties of melt-drawn PCL/PLA microfibrillar composites

    Directory of Open Access Journals (Sweden)

    I. Kelnar

    2016-05-01

    Full Text Available The study deals with the modification of mechanical properties of poly (!-caprolactone (PCL/poly(lactic acid (PLA system using the microfibrillar composite (MFC concept. As the in-situ formation of PLA fibrils by melt drawing was impossible due to flow instability during extrusion, the system was modified by adding halloysite nanotubes (HNT using different mixing protocols. The resulting favourable effect on the rheological parameters of the components allowed successful melt drawing. Consequently, PLA fibrils formation combined with the reinforcement of components by HNT and increased PLA crystallinity lead to a biocompatible and biodegradable material with good performance suitable for a broad range of applications. The best results, comparable with analogous MFC modified with layered silicate (oMMT, have been achieved at a relatively low content of HNT of 3%, in spite of its lower reinforcing ability in a single nanocomposite. This indicates that modifying MFC by HNT, including fibrils and interface parameters, is more complex in comparison with the undrawn system.

  10. Incorporation of stromal cell-derived factor-1α in PCL/gelatin electrospun membranes for guided bone regeneration.

    Science.gov (United States)

    Ji, Wei; Yang, Fang; Ma, Jinling; Bouma, Margaretha J; Boerman, Otto C; Chen, Zhi; van den Beucken, Jeroen J J P; Jansen, John A

    2013-01-01

    The goal of this work was to evaluate the effect of membrane functionalization with a chemotactic factor on cell recruitment and bone formation in order to develop a bioactive membrane for guided bone regeneration (GBR) applications. To this end, GBR membranes were prepared by electrospinning using poly(ε-caprolactone) (PCL) blended with type B-gelatin, and functionalized with stromal cell derived factor-1α (SDF-1α) via physical adsorption. Firstly, the obtained membranes were evaluated in vitro for SDF-1α release and chemotactic effect on bone marrow stromal cells (BMSCs). Subsequently, in vivo BMSCs recruitment and bone regeneration in response to SDF-1α loaded PCL/gelatin electrospun membranes were assessed in rat cranial defects. The results showed that PCL/gelatin electrospun membranes provided a diffusion-controlled SDF-1α release profile. Furthermore, the membranes loaded with different amounts of SDF-1α (50-400 ng) significantly induced stimulated chemotactic migration of BMSCs in vitro without dose-dependent effects. Eight weeks after implantation in rat cranial defects, SDF-1α loaded membranes yielded a 6-fold increase in the amount of bone formation compared to the bare membranes, albeit that contribution of in vivo BMSCs recruitment to the bone regeneration could not be ascertained. In conclusion, the results of current study indicate the potential for using SDF-1α loaded PCL/gelatin electrospun membrane as a bioactive membrane, which is beneficial for optimizing clinical application of GBR strategies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Controlled release of metronidazole from composite poly-ε-caprolactone/alginate (PCL/alginate) rings for dental implants.

    Science.gov (United States)

    Lan, Shih-Feng; Kehinde, Timilehin; Zhang, Xiangming; Khajotia, Sharukh; Schmidtke, David W; Starly, Binil

    2013-06-01

    Dental implants provide support for dental crowns and bridges by serving as abutments for the replacement of missing teeth. To prevent bacterial accumulation and growth at the site of implantation, solutions such as systemic antibiotics and localized delivery of bactericidal agents are often employed. The objective of this study was to demonstrate a novel method of controlled localized delivery of antibacterial agents to an implant site using a biodegradable custom fabricated ring. The study involved incorporating a model antibacterial agent (metronidazole) into custom designed poly-ε-caprolactone/alginate (PCL/alginate) composite rings to produce the intended controlled release profile. The rings can be designed to fit around the body of any root form dental implants of various diameters, shapes and sizes. In vitro release studies indicate that pure (100%) alginate rings exhibited an expected burst release of metronidazole in the first few hours, whereas Alginate/PCL composite rings produced a medium burst release followed by a sustained release for a period greater than 4 weeks. By varying the PCL/alginate weight ratios, we have shown that we can control the amount of antibacterial agents released to provide the minimal inhibitory concentration (MIC) needed for adequate protection. The fabricated composite rings have achieved a 50% antibacterial agent release profile over the first 48 h and the remaining amount slowly released over the remainder of the study period. The PCL/alginate agent release characteristic fits the Ritger-Peppas model indicating a diffusion-based mechanism during the 30-day study period. The developed system demonstrates a controllable drug release profile and the potential for the ring to inhibit bacterial biofilm growth for the prevention of diseases such as peri-implantitis resulting from bacterial infection at the implant site. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. ESTUDIO FISICOQUÍMICO DE MEZCLAS DE ALMIDÓN TERMOPLÁSTICO (TPS Y POLICAPROLACTONA (PCL

    Directory of Open Access Journals (Sweden)

    JOSE MINA H.

    Full Text Available Se estudiaron las propiedades físico-químicas de un almidón termoplástico (TPS de yuca, plastificado con glicerol, y el efecto de la incorporación de policaprolactona (PCL en el desarrollo de tres mezclas binarias TPS-PCL a proporciones 60-40, 50-50 y 40-60. El estudio inició con la preparación por extrusión del TPS y su posterior mezcla en caliente con la policaprolactona. El análisis de los resultados se enfocó principalmente a la identificación y seguimiento de la retrogradación, que se dio en el almidón termoplástico para diferentes tiempos de acondicionamiento (a 54% H.R. y 25ºC. Con el proceso de plastificación del almidón se generó una masa predominantemente amorfa, evidenciada por los resultados obtenidos con SEM, DRX y FTIR. Con la incorporación de la PCL se obtuvieron mezclas inmiscibles, en las cuales el TPS se constituyó en la fase dispersa y que conservaron una tendencia en la variación de las propiedades con el tiempo de acondicionamiento, similar a la observada en el TPS solo; indicando este hecho que las interacciones físico-químicas generadas entre el TPS y la policaprolactona no fueron lo suficientemente fuertes, como para incidir en la variación estructural del TPS, la cual se dio independiente del contenido de PCL.

  13. Drug loaded homogeneous electrospun PCL/gelatin hybrid nanofiber structures for anti-infective tissue regeneration membranes.

    Science.gov (United States)

    Xue, Jiajia; He, Min; Liu, Hao; Niu, Yuzhao; Crawford, Aileen; Coates, Phil D; Chen, Dafu; Shi, Rui; Zhang, Liqun

    2014-11-01

    Infection is the major reason for guided tissue regeneration/guided bone regeneration (GTR/GBR) membrane failure in clinical application. In this work, we developed GTR/GBR membranes with localized drug delivery function to prevent infection by electrospinning of poly(ε-caprolactone) (PCL) and gelatin blended with metronidazole (MNA). Acetic acid (HAc) was introduced to improve the miscibility of PCL and gelatin to fabricate homogeneous hybrid nanofiber membranes. The effects of the addition of HAc and the MNA content (0, 1, 5, 10, 20, 30, and 40 wt.% of polymer) on the properties of the membranes were investigated. The membranes showed good mechanical properties, appropriate biodegradation rate and barrier function. The controlled and sustained release of MNA from the membranes significantly prevented the colonization of anaerobic bacteria. Cells could adhere to and proliferate on the membranes without cytotoxicity until the MNA content reached 30%. Subcutaneous implantation in rabbits for 8 months demonstrated that MNA-loaded membranes evoked a less severe inflammatory response depending on the dose of MNA than bare membranes. The biodegradation time of the membranes was appropriate for tissue regeneration. These results indicated the potential for using MNA-loaded PCL/gelatin electrospun membranes as anti-infective GTR/GBR membranes to optimize clinical application of GTR/GBR strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Micelles based on amphiphilic PCL-PEO triblock and star-shaped diblock copolymers: Potential in drug delivery applications.

    Science.gov (United States)

    Quaglia, Fabiana; Ostacolo, Luisanna; Nese, Giuseppe; Canciello, Mariarosaria; De Rosa, Giuseppe; Ungaro, Francesca; Palumbo, Rosario; La Rotonda, Maria Immacolata; Maglio, Giovanni

    2008-12-01

    In this work, the potential in drug nanodelivery of micelles made from poly(epsilon-caprolactone) (PCL) and poly (ethyleneoxide) (PEO) copolymers with triblock and star-diblock architectures was explored. Linear and 4-arm star-shaped PCL macromers with two or four --OH end groups were prepared by ring-opening polymerization of CL and condensed with alpha-methoxy-omega-carboxy-PEO. The resulting amphiphilic copolymers were characterized by (1)H NMR, size exclusion chromatography, and differential scanning calorimetry. Separate PCL and PEO crystalline phases were observed for both copolymers. Copolymers self-assembled in water giving critical association concentrations in the range 0.010-0.023 mg/mL. Micelles with a size of 32-45 nm were prepared by dialysis and characterized for hydrodynamic diameter and surface charge. Their potential as nanocarriers in drug delivery applications was evaluated too. Micelles were nontoxic to both Red blood cells and HeLa cells. Complement activation experiments indicated that micelles can escape the reticuloendothelial system once intravenously injected. Finally, a different uptake on HeLa cells was found for micelles obtained from triblock and star-shaped copolymers. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

  15. Comparative Efficacies of a 3D-Printed PCL/PLGA/β-TCP Membrane and a Titanium Membrane for Guided Bone Regeneration in Beagle Dogs

    OpenAIRE

    Jin-Hyung Shim; Joo-Yun Won; Su-Jin Sung; Dong-Hyuk Lim; Won-Soo Yun; Young-Chan Jeon; Jung-Bo Huh

    2015-01-01

    This study was conducted to evaluate the effects of a 3D-printed resorbable polycaprolactone/poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PCL/PLGA/β-TCP) membrane on bone regeneration and osseointegration in areas surrounding implants and to compare results with those of a non-resorbable titanium mesh membrane. After preparation of PCL/PLGA/β-TCP membranes using extrusion-based 3D printing technology; mechanical tensile testing and in vitro cell proliferation testing were performed. ...

  16. Factor structure, internal consistency and reliability of the Posttraumatic Stress Disorder Checklist (PCL: an exploratory study Estrutura fatorial, consistência interna e confiabilidade do Posttraumatic Stress Disorder Checklist (PCL: um estudo exploratório

    Directory of Open Access Journals (Sweden)

    Eduardo de Paula Lima

    2012-01-01

    Full Text Available INTRODUCTION: Posttraumatic stress disorder (PTSD is an anxiety disorder resulting from exposure to traumatic events. The Posttraumatic Stress Disorder Checklist (PCL is a self-report measure largely used to evaluate the presence of PTSD. OBJECTIVE: To investigate the internal consistency, temporal reliability and factor validity of the Portuguese language version of the PCL used in Brazil. METHODS: A total of 186 participants were recruited. The sample was heterogeneous with regard to occupation, sociodemographic data, mental health history, and exposure to traumatic events. Subjects answered the PCL at two occasions within a 15 days’ interval (range: 5-15 days. RESULTS: Cronbach’s alpha coefficients indicated high internal consistency for the total scale (0.91 and for the theoretical dimensions of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV (0.83, 0.81, and 0.80. Temporal reliability (test-retest was high and consistent for different cutoffs. Maximum likelihood exploratory factor analysis (EFA was conducted and oblique rotation (Promax was applied. The Kaiser-Meyer-Olkin (KMO index (0.911 and Bartlett’s test of sphericity (χ² = 1,381.34, p INTRODUÇÃO: O transtorno do estresse pós-traumático (TEPT é um transtorno de ansiedade decorrente da exposição a eventos traumáticos. Entre as medidas de avaliação dos sintomas, destaca-se o Posttraumatic Stress Disorder Checklist (PCL. OBJETIVO: Investigar a consistência interna, a confiabilidade temporal e a validade fatorial da versão do PCL em português, utilizada no Brasil. MÉTODOS: Participaram do estudo 186 indivíduos heterogêneos em relação a ocupação, características sociodemográficas, histórico de saúde mental e exposição a eventos traumáticos. O PCL foi aplicado em dois momentos considerando um intervalo máximo de 15 dias (intervalo: 5-15 dias. RESULTADOS: A consistência interna (alfa de Cronbach foi adequada para a escala

  17. Impact of motility and chemotaxis features of the rhizobacterium Pseudomonas chlororaphis PCL1606 on its biocontrol of avocado white root rot.

    Science.gov (United States)

    Polonio, Álvaro; Vida, Carmen; de Vicente, Antonio; Cazorla, Francisco M

    2017-06-01

    The biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 has the ability to protect avocado plants against white root rot produced by the phytopathogenic fungus Rosellinia necatrix. Moreover, PCL1606 displayed direct interactions with avocado roots and the pathogenic fungus. Thus, nonmotile (flgK mutant) and non-chemotactic (cheA mutant) derivatives of PCL1606 were constructed to emphasize the importance of motility and chemotaxis in the biological behaviour of PCL1606 during the biocontrol interaction. Plate chemotaxis assay showed that PCL1606 was attracted to the single compounds tested, such as glucose, glutamate, succinate, aspartate and malate, but no chemotaxis was observed to avocado or R. necatrix exudates. Using the more sensitive capillary assay, it was reported that smaller concentrations (1 mM) of single compounds elicited high chemotactic responses, and strong attraction was confirmed to avocado and R. necatrix exudates. Finally, biocontrol experiments revealed that the cheA and fglK derivative mutants reduced root protection against R. necatrix, suggesting an important role for these biological traits in biocontrol by P. chlororaphis PCL1606. [Int Microbiol 20(2):94-104 (2017)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  18. Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application.

    Science.gov (United States)

    Fereshteh, Zeinab; Nooeaid, Patcharakamon; Fathi, Mohammadhossein; Bagri, Akbar; Boccaccini, Aldo R

    2015-09-01

    This article presents data related to the research article entitled "The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering" [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research.

  19. Development and characterization of methoxy poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) micelles as vehicles for the solubilization and delivery of tacrolimus.

    Science.gov (United States)

    Ali, Raisuddin; Farah, Abubakar; Binkhathlan, Ziyad

    2017-02-01

    Tacrolimus is a potent immunosuppressant; however, it suffers from several problems such as poor water solubility (4-12 μg/mL), low and variable oral bioavailability in patients, and narrow therapeutic window that could not be solved by the currently available i.v. formulation (Prograf®). Moreover, Prograf® contains HCO-60 (PEGylated castor oil) as a surfactant, which is reported to cause several side effects including hypersensitivity reactions. Therefore, the aim of the present study was to investigate the potential of PEO-b-PCL polymeric micelles as alternative vehicles for the solubilization and delivery of tacrolimus. Four PEO-b-PCL block copolymers, with different molecular weights of PCL, were synthesized by ring opening polymerization of ε-caprolactone using methoxy polyethylene oxide (5,000 g mol(-1)) as initiator and stannous octoate as catalyst. Synthesized copolymers were characterized for their average molecular weights and polydispersity index by (1)H NMR and gel permeation chromatography (GPC), respectively. Drug-free micelles of PEO-b-PCL were prepared through a co-solvent evaporation method using acetone as the organic co-solvent. Tacrolimus-loaded micelles were prepared using the same method with different initial amounts of drug. Prepared micelles were characterized for their mean diameter size and polydispersity of the micellar population by dynamic light scattering, and an HPLC assay was used to determine the encapsulation efficiency of tacrolimus. The average molecular weights of the synthesized copolymers were in the range of 8,400-28,000 with narrow distributions (PDI = 1.06-1.11). The copolymers were designated according to the degree of polymerization of ε-caprolactone, namely PEO114-b-PCL30, PEO114-b-PCL60, PEO114-b-PCL120, and PEO114-b-PCL200. All the prepared micelles were having diameters sizes less than 100 nm with narrow distributions. The highest drug solubilization was achieved with PEO114-b-PCL120, where the aqueous

  20. Inverse solutions for tilting orthogonal double prisms.

    Science.gov (United States)

    Li, Anhu; Ding, Ye; Bian, Yongming; Liu, Liren

    2014-06-10

    An analytical reverse solution and actual examples are given to show how to direct a laser beam from a pair of orthogonal prisms to given targets in free space. Considering the influences of double-prism structural parameters, a lookup table method to seek the numerical reverse solution of each prism's tilting angle is also proposed for steering the double-prism orientation to track a target position located in the near field. Some case studies, as well as a specified elliptical target trajectory scanned by the cam-based driving double prisms, exhibit the significant application values of the theoretical derivation. The analytic reverse and numerical solutions can be generalized to investigate the synthesis of scanning patterns and the controlling strategy of double-prism tilting motion, the potentials of which can be explored to perform the orientation and position tracking functions in applications of precision engineering fields.

  1. Short- and long-term recidivism prediction of the PCL-R and the effects of age: a 24-year follow-up.

    Science.gov (United States)

    Olver, Mark E; Wong, Stephen C P

    2015-01-01

    We prospectively examined the short- and long-term prediction of several recidivism outcomes as a function of psychopathy and age in a sample of 273 Canadian federal inmates with an average 24 years post-release follow-up. Offenders were rated using the original 22-item Hare Psychopathy Checklist (PCL: Hare, 1980) based on extensive archival file information, and the ratings were used to compute the Psychopathy Checklist-Revised (Hare, 2003) and the 4 facet scores. PCL-R total scores and the Lifestyle and Antisocial facets, but not the Interpersonal and Affective facets, showed mostly small and some moderate predictive efficacy for general and nonviolent recidivism over 3-, 5-, 10-, and 20-year fixed follow-ups, and predicted violence recidivism at shorter follow-ups. Age at release was negatively correlated with all recidivism outcomes and follow-up periods for both high and low PCL-R rated offenders, and uniquely predicted all recidivism outcomes after controlling for the PCL-R using Cox regression survival analysis. Increased age was consistently linked to recidivism reduction even for psychopathic offenders. The results showed that both PCL-R scores and age contributed to the prediction of recidivism; however, the PCL-R facets made differential contributions that varied with the type of offense (violent vs. nonviolent) and follow-up time (shorter vs. longer). The results have implications for both risk assessment using the PCL-R and potentially for risk reduction interventions. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  2. TiO{sub 2}/PCL hybrid materials synthesized via sol–gel technique for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, M., E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Bollino, F.; Papale, F. [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Marciano, S.; Pacifico, S. [Department Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta (Italy)

    2015-02-01

    The aim of the present work has been the synthesis of organic/inorganic hybrid materials based on titanium dioxide and poly(ε-caprolactone) (PCL) to be used in the biomedical field. Several materials have been synthesized using sol–gel methods by adding different amounts of polymer to the inorganic sol. The obtained gels have been characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The FT-IR data allowed us to hypothesize that the structure formed was that of an interpenetrating network, realized by hydrogen bonds between Ti-OH groups in the sol–gel intermediate species and carbonyl groups in the polymer repeating units. SEM and AFM analyses highlighted that the obtained materials were nanostructurated hybrids. To evaluate the biological properties of the hybrids, their bioactivity and cytotoxicity were investigated as a function of the PCL amount. The bioactivity of the synthesized systems was proven by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating human blood plasma (SBF). MTT cytotoxicity tests and Trypan Blue dye exclusion tests were carried out exposing NIH-3T3 mouse embryonic fibroblasts for 24 and 48 h to extracts from the investigated hybrid materials. The results showed that all the hybrids had a non-cytotoxic effect on target cells. - Highlights: • TiO{sub 2}/PCL hybrids were obtained by the sol–gel process for biomedical applications. • Synthesized materials were found to be first-class hybrid nanocomposites. • Hybrids appear to be bioactive, a fundamental characteristic for osseointegration. • MTT and Trypan Blue viability test show that the materials are biocompatible. • The organic phase is able to modulate the biocompatibility of the materials.

  3. Data on physicochemical properties of active films derived from plantain flour/PCL blends developed under reactive extrusion conditions

    Directory of Open Access Journals (Sweden)

    Tomy J. Gutiérrez

    2017-12-01

    Full Text Available The data given below relates to the research paper entitled: “Eco-friendly films prepared from plantain flour/PCL blends under reactive extrusion conditions using zirconium octanoate as a catalyst”, recently published by our research group [1]. This article provides information concerning the physicochemical properties of the above-mentioned film systems: thickness, density, opacity, moisture content and surface moisture. Keywords: Active films, Antimicrobial properties, Cross-linking, Poly(ε-caprolactone, Starchy

  4. Double Swing

    DEFF Research Database (Denmark)

    Clausen, Lisbeth

    2017-01-01

    There are two main streams of understanding intercultural communication. The “classic” transmission models include the basic elements of communication involved in sending messages from a sender to a receiver. These models enable analysis of all communication elements and effects by focusing...... on sameness in communication. In contrast, Muneo Jay Yoshikawa's “double-swing” model of intercultural communication between the East and West is based on an eastern understanding of dialogue, collaborative communication, and co-creation of meaning. The double-swing model enables an understanding...... of communication as an ongoing encounter where both sender and receiver have mutual respect. It has four modes of communication: the ethnocentric, the dialectic, the control, and the dialogic. Both models have something to offer intercultural communication, but the double-swing model enables a worldview...

  5. Eco-friendly films prepared from plantain flour/PCL blends under reactive extrusion conditions using zirconium octanoate as a catalyst.

    Science.gov (United States)

    Gutiérrez, Tomy J; Alvarez, Vera A

    2017-12-15

    Plantain flour (Musa ssp., group AAB, sub-group clone Harton)/poly(ε-caprolactone) (PCL) blends, containing glycerol as a plasticizer, were prepared by reactive extrusion (REx) in a twin-screw extruder using zirconium octanoate (Zr(Oct)4) as a catalyst, followed by thermo-compression molding for film development. The films were then characterized in terms of their: infrared (FTIR) spectra, water solubility, thermogravimetric (TGA) curves, differential scanning calorimetry (DSC) thermograms, and X-ray diffraction (XDR) diffractograms, as well as their microstructural, mechanical and antimicrobial properties in order to (1) compare the effects of PCLs with two different molecular weights (Mw) on the characteristics of the plantain flour/PCL blends, and (2) determine whether using Zr(Oct)4 in the production of active composite polymer materials improves their properties. The plantain flour/PCL blends were all developed successfully. The higher Mw PCL gave more hydrophobic and thermally stable films with improved mechanical properties. The addition of the Zr(Oct)4 catalyst to the plantain flour/PCL blends also resulted in films with similar characteristics to those described above, due to the cross-linking of the polymers. In addition, the films containing the catalyst showed antimicrobial activity against Escherichia coli O157:H7 and Staphylococcus aureus indicating a dual effect of Zr(Oct)4, and making it an attractive alternative for the development of active films. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Using MMPI-2-RF Correlates to Elucidate the PCL-R and Its Four Facets in a Sample of Male Forensic Psychiatric Patients.

    Science.gov (United States)

    Klein Haneveld, Evelyn; Kamphuis, Jan H; Smid, Wineke; Forbey, Johnathan D

    2017-01-01

    This study documents the associations between the MMPI-2-RF (Ben-Porath & Tellegen, 2008 ) scale scores and the Psychopathy Checklist Revised (PCL-R; Hare, 2003 ) facet scores in a forensic psychiatric sample. Objectives were to determine how the MMPI-2-RF scales might enhance substantive understanding of the nature of the 4 PCL-R facets and to discern possible implications for the treatment of psychopathic patients. A sample of 127 male forensic psychiatric offenders admitted to a Dutch forensic psychiatric hospital completed the PCL-R and the MMPI-2. Exploratory stepwise regression analyses assessed the prediction of the PCL-R total and its facet scores from MMPI-2-RF scales at its 3 hierarchical levels. Conceptually meaningful results emerged at each level of the MMPI-2-RF hierarchy, including several consistent differences between predictor sets across the facets. Interestingly, ideas of persecution (RC6) was a specific predictor of PCL-R Facet 2, a facet noted for its association with treatment failure. Results are compared and contrasted to the extant body of empirical work to date, and some tentative clinical implications are offered.

  7. Acetal-Linked Paclitaxel Polymeric Prodrug Based on Functionalized mPEG-PCL Diblock Polymer for pH-Triggered Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yinglei Zhai

    2017-12-01

    Full Text Available The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX prodrug micelles based on functionalized poly(ethylene glycol-poly(ε-caprolactone (mPEG-PCL diblock polymer with an acid-cleavable acetal (Ace linkage (mPEG-PCL-Ace-PTX. The mPEG-PCL-Ace-PTX5 with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX5 micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX5 micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy.

  8. Study of smart antibacterial PCL-xFe3O4thin films using mouse NIH-3T3 fibroblast cells in vitro.

    Science.gov (United States)

    Pai B, Ganesh; Kulkarni, Ajay V; Jain, Shilpee

    2017-05-01

    Surface energy plays a major role in prokaryotic and eukaryotic cell interactions with biomedical devices. In the present study, poly(ε-caprolactone)-xFe 3 O 4 nanoparticles (PCL-xFO NPs; x = 0, 10, 20, 30, 40, 60 wt% FO concentration in PCL) composite thin films were developed for skin tissue regeneration. The surface properties in terms of roughness, surface energy, wettability of the thin films were altered with the incorporation of Fe 3 O 4 NPs. These thin films show antimicrobial properties and cyto-compatibility with NIH 3T3 mouse embryonic fibroblast cells. The porosity and thickness of the films were controlled by varying RPM of the spin coater. Interestingly, at 1000 RPM the roughness of the film decreased with increasing concentrations of FO NPs in PCL, whereas the surface energy increased with increasing FO NPs concentrations. Furthermore, the spreading of NIH-3T3 cells grown on PCL-xFO thin films was less as compared to control (TCPS), however cells overcame this effect after 48 h of seeding and cells spread similarly to those grown on TCPS after 48 h. Also, the incorporation of FO NPs in thin films induced inner membrane permeabilization in E. coli bacteria leading to bacterial cell death. The viability of E. coli bacteria decreased with increasing concentration of FO NPs in PCL. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 795-804, 2017. © 2016 Wiley Periodicals, Inc.

  9. A novel therapy strategy for bile duct repair using tissue engineering technique: PCL/PLGA bilayered scaffold with hMSCs.

    Science.gov (United States)

    Zong, Chen; Wang, Meicong; Yang, Fuchun; Chen, Guojun; Chen, Jiarong; Tang, Zihua; Liu, Quanwen; Gao, Changyou; Ma, Lie; Wang, Jinfu

    2017-04-01

    The current clinical treatments for complications caused by hepatobiliary surgery still have some inevitable weakness. The aim of the study was to fabricate a tissue-engineered bile duct that utilized a novel bilayered polymer scaffold combined with human bone marrow-derived mesenchymal stem cells (hMSCs) for new treatment of biliary disease. The biocompatibility of polycaprolactone (PCL) (PCL)/poly(lactide-co-glycolide) (PLGA) scaffold with hMSCs was first examined, and the hMSC-PCL/PLGA constructs (MPPCs) prepared. The MPPCs and blank scaffolds were then transplanted into 18 pigs for evaluation its efficacy on bile duct repairing, respectively. In vitro, the PCL/PLGA scaffold was verified to support the adhesion, proliferation and matrix deposition of hMSCs. There was no sign of bile duct narrowing and cholestasis in all experimental animals. At 6 months, the MPPCs had a superior repairing effect on the bile duct injury, compared with the blank PCL/PLGA scaffolds. Therefore, the implanted scaffolds could not only support the biliary tract and allow free bile flow but also had direct or indirect positive effects on repair of injured bile duct. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  11. Improved Safety for Molecular Diagnosis of Classical Rabies Viruses by Use of a TaqMan Real-Time Reverse Transcription-PCR “Double Check” Strategy▿ †

    Science.gov (United States)

    Hoffmann, B.; Freuling, C. M.; Wakeley, P. R.; Rasmussen, T. B.; Leech, S.; Fooks, A. R.; Beer, M.; Müller, T.

    2010-01-01

    To improve the diagnosis of classical rabies virus with molecular methods, a validated, ready-to-use, real-time reverse transcription-PCR (RT-PCR) assay was developed. In a first step, primers and 6-carboxyfluorescien-labeled TaqMan probes specific for rabies virus were selected from the consensus sequence of the nucleoprotein gene of 203 different rabies virus sequences derived from GenBank. The selected primer-probe combination was highly specific and sensitive. During validation using a sample set of rabies virus strains from the virus archives of the Friedrich-Loeffler-Institut (FLI; Germany), the Veterinary Laboratories Agency (VLA; United Kingdom), and the DTU National Veterinary Institute (Lindholm, Denmark), covering the global diversity of rabies virus lineages, it was shown that both the newly developed assay and a previously described one had some detection failures. This was overcome by a combined assay that detected all samples as positive. In addition, the introduction of labeled positive controls (LPC) increased the diagnostic safety of the single as well as the combined assay. Based on the newly developed, alternative assay for the detection of rabies virus and the application of LPCs, an improved diagnostic sensitivity and reliability can be ascertained for postmortem and intra vitam real-time RT-PCR analyses in rabies reference laboratories. PMID:20739489

  12. Fabrication of hydroxyapatite-baghdadite nanocomposite scaffolds coated by PCL/Bioglass with polyurethane polymeric sponge technique

    Directory of Open Access Journals (Sweden)

    Ebrahim Karamian

    2017-07-01

    Full Text Available Objecttive (s: Silicate bioceramics like Baghdadite with chemical formula Ca3ZrSi2O9, has attracted the attention of researchers in biomedical field due to its remarkable in-vitro and in-vivo bioactivity and mechanical properties.Materials and Methods: Therefore, in the current study the baghdadite powder with Sol-Gel method was synthesized. Then, hydroxyapatite/Baghdadite (HA/Bagh scaffolds were prepared by the replacing the polyurethane polymeric sponge technique. Afterwhile, the ceramic scaffolds were sintered at 1150ºC for 3 h. The prepared scaffold was then coated by polycaprolactone/bioglass (PCL/BG polymer nanocomposite. Results: Bioactivity and biomineralization in the simulated body fluid (SBF revealed that the nanocomposite scaffolds coate with PCL/BG had significant bioactivity properties. The morophology and microstructure investigation of soaked samples in SBF indicate that bone-like apatite formed on the surfaces. Also, ion release in SBF containing the scaffolds was measured by inductively coupled plasma (ICP analysis. The nucleation positions of apatite crystals were areas with high silicon containing, Si+4 ion positions.Conclusion: The study indicates that scaffold containing 30 wt. % baghdadite had proper bioactivity behaviordue to its ability to form bone-like apatite on the surface of specimens.

  13. The mPEG-PCL Copolymer for Selective Fermentation of Staphylococcus lugdunensis Against Candida parapsilosis in the Human Microbiome.

    Science.gov (United States)

    Kao, Ming-Shan; Wang, Yanhan; Marito, Shinta; Huang, Stephen; Lin, Wan-Zhen; Gangoiti, Jon A; Barshop, Bruce A; Hyun, Choi; Lee, Woan-Ruah; Sanford, James A; Gallo, Richard L; Ran, Yuping; Chen, Wan-Tzu; Huang, Chun-Jen; Hsieh, Ming-Fa; Huang, Chun-Ming

    2016-08-01

    Many human skin diseases, such as seborrheic dermatitis, potentially occur due to the over-growth of fungi. It remains a challenge to develop fungicides with a lower risk of generating resistant fungi and non-specifically killing commensal microbes. Our probiotic approaches using a selective fermentation initiator of skin commensal bacteria, fermentation metabolites or their derivatives provide novel therapeutics to rein in the over-growth of fungi. Staphylococcus lugdunensis (S. lugdunensis) bacteria and Candida parapsilosis (C. parapsilosis) fungi coexist in the scalp microbiome. S. lugdunensis interfered with the growth of C. parapsilosis via fermentation. A methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-PCL) copolymer functioned as a selective fermentation initiator of S. lugdunensis, selectively triggering the S. lugdunensis fermentation to produce acetic and isovaleric acids. The acetic acid and its pro-drug diethyleneglycol diacetate (Ac-DEG-Ac) effectively suppressed the growth of C. parapsilosis in vitro and impeded the fungal expansion in the human dandruff. We demonstrate for the first time that S. lugdunensis is a skin probiotic bacterium that can exploit mPEG-PCL to yield fungicidal short-chain fatty acids (SCFAs). The concept of bacterial fermentation as a part of skin immunity to re-balance the dysbiotic microbiome warrants a novel avenue for studying the probiotic function of the skin microbiome in promoting health.

  14. A Solvent-Free Surface Suspension Melt Technique for Making Biodegradable PCL Membrane Scaffolds for Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Ratima Suntornnond

    2016-03-01

    Full Text Available In tissue engineering, there is limited availability of a simple, fast and solvent-free process for fabricating micro-porous thin membrane scaffolds. This paper presents the first report of a novel surface suspension melt technique to fabricate a micro-porous thin membrane scaffolds without using any organic solvent. Briefly, a layer of polycaprolactone (PCL particles is directly spread on top of water in the form of a suspension. After that, with the use of heat, the powder layer is transformed into a melted layer, and following cooling, a thin membrane is obtained. Two different sizes of PCL powder particles (100 µm and 500 µm are used. Results show that membranes made from 100 µm powders have lower thickness, smaller pore size, smoother surface, higher value of stiffness but lower ultimate tensile load compared to membranes made from 500 µm powder. C2C12 cell culture results indicate that the membrane supports cell growth and differentiation. Thus, this novel membrane generation method holds great promise for tissue engineering.

  15. Influence of the HCR-20, LS/CMI, and PCL-R on decisions about parole suitability among lifers.

    Science.gov (United States)

    Guy, Laura S; Kusaj, Cliff; Packer, Ira K; Douglas, Kevin S

    2015-06-01

    Among 5,181 inmates indeterminately sentenced to life in California who were evaluated for parole suitability between January 2009 and November 2010, 11% were granted parole. After administration of the HCR-20, LS/CMI, and PCL-R, psychologists judged most inmates (78%) to be at low or moderate risk for future violence. This overall risk rating (ORR) was significantly associated with parole suitability decisions. Moderate to large associations were observed between the ORR and all risk indices. The HCR-20 Clinical and Risk Management scales demonstrated the strongest associations with parole suitability decisions. Among the LS/CMI scales, Procriminal Attitudes and Leisure/Recreation were most predictive of failure to obtain parole. PCL-R scores had little influence on parole suitability decisions beyond the HCR-20 and LS/CMI. Overall, findings suggest parole board members' decisions were consistent with empirically supported practice, in that individuals assessed to be at relatively low risk were far more likely to be granted parole than those assessed to be at moderate or high risk for future violence. (c) 2015 APA, all rights reserved).

  16. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  17. M184I/V substitutions and E138K/M184I/V double substitutions in HIV reverse transcriptase do not significantly affect the antiviral activity of EFdA.

    Science.gov (United States)

    Oliveira, Maureen; Brenner, Bluma G; Xu, Hongtao; Ibanescu, Ruxandra-Ilinca; Mesplède, Thibault; Wainberg, Mark A

    2017-11-01

    4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a potent nucleoside analogue inhibitor of HIV that has an unusually long half-life. Cell culture selections with either EFdA or lamivudine using both subtype B and non-B clinical isolates selected the M184I/V substitutions in reverse transcriptase (RT). Unlike lamivudine, however, EFdA retained significant activity against viruses containing the M184I/V substitutions. In other clinical trials that evaluated rilpivirine together with emtricitabine in first-line therapy, the emergence of both the M184I/V and E138K mutations in RT was demonstrated. Moreover, the M184I/V and E138K substitutions were shown to be compensatory for each other with regard to both efficiency of RT activity and viral replicative capacity. This creates concern that E138K might emerge as a compensatory mutation for M184I/V in the aftermath of the use of EFdA. We wished to determine whether the E138K mutation in HIV RT together with M184I/V would compromise the activity of EFdA. Recombinant viruses containing the M184I/V and/or E138K substitutions were generated by site-directed mutagenesis and evaluated in tissue culture for susceptibility to various nucleoside compounds, including EFdA. Susceptibility to EFdA was retained in M184I/V viruses that also contained the E138K substitution. Moreover, the E138K substitution was not generated in these studies under selection pressure with EFdA. These findings help to alleviate concern that EFdA may not be active against viruses that contain both the M184I/V and E138K substitutions in RT.

  18. Evaluation of 3D printed PCL/PLGA/β-TCP versus collagen membranes for guided bone regeneration in a beagle implant model.

    Science.gov (United States)

    Won, J-Y; Park, C-Y; Bae, J-H; Ahn, G; Kim, C; Lim, D-H; Cho, D-W; Yun, W-S; Shim, J-H; Huh, J-B

    2016-10-07

    Here, we compared 3D-printed polycaprolactone/poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PCL/PLGA/β-TCP) membranes with the widely used collagen membranes for guided bone regeneration (GBR) in beagle implant models. For mechanical property comparison in dry and wet conditions and cytocompatibility determination, we analyzed the rate and pattern of cell proliferation of seeded fibroblasts and preosteoblasts using the cell counting kit-8 assay and scanning electron microscopy. Osteogenic differentiation was verified using alizarin red S staining. At 8 weeks following implantation in vivo using beagle dogs, computed tomography and histological analyses were performed after sacrifice. Cell proliferation rates in vitro indicated that early cell attachment was higher in collagen than in PCL/PLGA/β-TCP membranes; however, the difference subsided by day 7. Similar outcomes were found for osteogenic differentiation, with approximately 2.5 times greater staining in collagen than PCL/PLGA/β-TCP, but without significant difference by day 14. In vivo, bone regeneration in the defect area, represented by new bone formation and bone-to-implant contact, paralleled those associated with collagen membranes. However, tensile testing revealed that whereas the PCL/PLGA/β-TCP membrane mechanical properties were conserved in both wet and dry states, the tensile property of collagen was reduced by 99% under wet conditions. Our results demonstrate in vitro and in vivo that PCL/PLGA/β-TCP membranes have similar levels of biocompatibility and bone regeneration as collagen membranes. In particular, considering that GBR is always applied to a wet environment (e.g. blood, saliva), we demonstrated that PCL/PLGA/β-TCP membranes maintained their form more reliably than collagen membranes in a wet setting, confirming their appropriateness as a GBR membrane.

  19. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  20. Double screening

    Energy Technology Data Exchange (ETDEWEB)

    Gratia, Pierre [Department of Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Hu, Wayne [Department of Astronomy and Astrophysics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Joyce, Austin [Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Ribeiro, Raquel H. [School of Physics and Astronomy, Queen Mary University of London,Mile End Road, London, E1 4NS (United Kingdom)

    2016-06-15

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

  1. Developing the PTSD Checklist-I/F for the DSM-IV (PCL-I/F: Assessing PTSD Symptom Frequency and Intensity in a Pilot Study of Male Veterans with Combat-Related PTSD

    Directory of Open Access Journals (Sweden)

    Ryan Holliday

    2015-02-01

    Full Text Available The widely used posttraumatic stress disorder (PTSD Checklist (PCL has established reliability and validity, but it does not differentiate posttraumatic symptom frequency from intensity as elements of posttraumatic symptom severity. Thus, the PCL in its existing form may not provide a comprehensive appraisal of posttraumatic symptomatology. Because of this, we modified the PCL to create the PCL-I/F that measures both frequency and intensity of PTSD symptoms via brief self-report. To establish validity and internal consistency of the PCL-I/F, we conducted a pilot study comparing PCL-I/F scores to structured diagnostic interview for PTSD (the Clinician Administered PTSD Scale [CAPS] in a male combat veteran sample of 92 participants. Statistically significant correlations between the PCL-I/F and the CAPS were found, suggesting initial validation of the PCL-I/F to screen and assess frequency and intensity of combat-related PTSD symptoms. Implications are discussed for screening and assessment of PTSD related to combat and non-combat trauma.

  2. Reverse logistics - a framework

    OpenAIRE

    Brito, Marisa; Dekker, Rommert

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of products, processes and actors. In addition we provide a decision framework for Reverse Logistics and we present it according to long, medium and short term decisions, i.e. strategic-tactic-operational decis...

  3. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  4. Biodegradation of blend films PVA/PVC, PVA/PCL in soil and soil with landfill leachate

    Directory of Open Access Journals (Sweden)

    Adriana de Campos

    2011-12-01

    Full Text Available This study investigated the biodegradation of blends films of poly(vinyl alcohol/poly(vinyl chloride (PVA/PVC and poly(vinyl alcohol/poly(caprolactone (PVA/PCL blends films prepared with dimethylformamide under a variety of conditions by respirometry, spectrophotometry (FTIR, scanning electron microscopy (SEM, and contact angle. The films were buried in the garden soil and in the soil mixed with the landfill leachate for 120 days at 28ºC. Significant levels of biodegradation were achieved in fairly short incubation times in the soil. The results indicated that PVA was the most biodegradable film in the soil and in the soil with the leachate.

  5. Genetic and functional characterization of the gene cluster directing the biosynthesis of putisolvin I and II in Pseudomonas putida strain PCL1445

    NARCIS (Netherlands)

    Dubern, J.F.; Coppoolse, E.R.; Stiekema, W.J.; Bloemberg, G.V.

    2008-01-01

    Pseudomonas putida PCL1445 secretes two cyclic lipopeptides, putisolvin I and putisolvin II, which possess a surface-tension-reducing ability, and are able to inhibit biofilm formation and to break down biofilms of Pseudomonas species including Pseudomonas aeruginosa. The putisolvin synthetase gene

  6. Immobilization of cross linked Col-I-OPN bone matrix protein on aminolysed PCL surfaces enhances initial biocompatibility of human adipogenic mesenchymal stem cells (hADMSC)

    Science.gov (United States)

    Kim, Young-Hee; Jyoti, Md. Anirban; Song, Ho-Yeon

    2014-06-01

    In bone tissue engineering surface modification is considered as one of the important ways of fabricating successful biocompatible material. Addition of biologically active functionality on the surfaces has been tried for improving the overall biocompatibility of the system. In this study poly-ɛ-caprolactone film surfaces have been modified through aminolysis and immobilization process. Collagen type I (COL-I) and osteopontin (OPN), which play an important role in osteogenesis, was immobilized onto PCL films followed by aminolysis treatment using 1,6-hexanediamine. Characterization of animolysed and immobilized surfaces were done by a number techniques using scanning electron microscopy (SEM), FT-IR, XPS, ninhydrin staining, SDS-PAGE and confocal microscopy and compared between the modified and un-modified surfaces. Results of the successive experiments showed that aminolysis treatment was homogeneously achieved which helped to entrap or immobilize Col-I-OPN proteins on surfaces of PCL film. In vitro studies with human adipogenic mesenchymal stem cells (hADMSC) also confirmed the attachment and proliferation of cells was better in modified PCL surfaces than the unmodified surfaces. SEM, confocal microscopy and MTT assay showed a significant increase in cell spreading, attachment and proliferations on the biofunctionalized surfaces compared to the unmodified PCL surfaces at all-time points indicating the success of surface biofunctionalization.

  7. Immobilization of cross linked Col-I–OPN bone matrix protein on aminolysed PCL surfaces enhances initial biocompatibility of human adipogenic mesenchymal stem cells (hADMSC)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Hee; Jyoti, Md. Anirban; Song, Ho-Yeon, E-mail: songmic@sch.ac.kr

    2014-06-01

    In bone tissue engineering surface modification is considered as one of the important ways of fabricating successful biocompatible material. Addition of biologically active functionality on the surfaces has been tried for improving the overall biocompatibility of the system. In this study poly-ε-caprolactone film surfaces have been modified through aminolysis and immobilization process. Collagen type I (COL-I) and osteopontin (OPN), which play an important role in osteogenesis, was immobilized onto PCL films followed by aminolysis treatment using 1,6-hexanediamine. Characterization of animolysed and immobilized surfaces were done by a number techniques using scanning electron microscopy (SEM), FT-IR, XPS, ninhydrin staining, SDS-PAGE and confocal microscopy and compared between the modified and un-modified surfaces. Results of the successive experiments showed that aminolysis treatment was homogeneously achieved which helped to entrap or immobilize Col-I–OPN proteins on surfaces of PCL film. In vitro studies with human adipogenic mesenchymal stem cells (hADMSC) also confirmed the attachment and proliferation of cells was better in modified PCL surfaces than the unmodified surfaces. SEM, confocal microscopy and MTT assay showed a significant increase in cell spreading, attachment and proliferations on the biofunctionalized surfaces compared to the unmodified PCL surfaces at all-time points indicating the success of surface biofunctionalization.

  8. Psychopathy and crime: testing the incremental validity of PCL-R-measured psychopathy as a predictor of general and violent recidivism.

    Science.gov (United States)

    Walters, Glenn D

    2012-10-01

    It has been argued that psychopathy plays a vital role in the criminal justice system. To test this assumption, the incremental validity of the psychopathy construct was examined in 198 male Canadian prison inmates serving time for nonsexual offenses and 122 male U. S. inmates undergoing forensic evaluations. When these two samples--which had been used previously to test the incremental validity of the four Psychopathy Checklist-Revised (PCL-R: Hare, 2003) facet scores (Walters, Wilson, & Glover, 2011)--were treated as a single group, second-order confirmatory factor analysis and item response theory principles indicated that a three-factor hierarchical model of the PCL-R facets (interpersonal, affective, lifestyle) fit the data better than a four-factor hierarchical model (interpersonal, affective, lifestyle, antisocial). When the two samples were examined separately, a composite of the first three PCL-R facets (interpersonal, affective, lifestyle) failed to predict general and violent recidivism above and beyond the contributions of age and criminal history. These results bring into question the utility of the psychopathy construct, as measured by Facets 1, 2, and 3 of the PCL-R, to predict important criminal justice outcomes like recidivism. Additional research using alternative measures of psychopathy and a wider array of outcome measures is required to determine the extent to which the psychopathy construct contributes to our understanding of criminal behavior. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  9. Influence of highly porous electrospun PLGA/PCL/nHA fibrous scaffolds on the differentiation of tooth bud cells in vitro

    NARCIS (Netherlands)

    Cai, X; Hoopen, S. Ten; Zhang, W.; Yi, C.; Yang, W; Yang, F.; Jansen, J.A.; Walboomers, X.F.; Yelick, P.C.

    2017-01-01

    In this study, we investigated the use of three-dimensional electrospun poly(lactic-co-glycolic acid)/poly(epsilon-caprolactone) (PLGA/PCL) scaffolds seeded and cultured with postnatal dental cells, for improved dental tissue regeneration. Wet-electrospinning combined with ultrasonic treatment was

  10. Predictive validity of risk assessments in juvenile offenders : Comparing the SAVRY, PCL:YV and YLS/CMI with unstructured clinical assessments

    NARCIS (Netherlands)

    Hilterman, E.L.B.; Nicholls, T.E.; van Nieuwenhuizen, Ch.

    2014-01-01

    This study examined the validity and reliability of the Structured Assessment of Violence Risk in Youth (SAVRY), the Youth Level of Service/Case Management Inventory (YLS/CMI), and the Psychopathy Checklist: Youth Version (PCL:YV) in a sample of Spanish adolescents with a community sanction (N =

  11. Incorporation of Calcium Containing Mesoporous (MCM-41-Type Particles in Electrospun PCL Fibers by Using Benign Solvents

    Directory of Open Access Journals (Sweden)

    Liliana Liverani

    2017-10-01

    Full Text Available The electrospinning technique is a versatile method for the production of fibrous scaffolds able to resemble the morphology of the native extra cellular matrix. In the present paper, electrospinning is used to fabricate novel SiO2 particles (type MCM-41 containing poly(epsilon-caprolactone (PCL fibers. The main aims of the present work are both the optimization of the particle synthesis and the fabrication of composite fibers, obtained using benign solvents, suitable as drug delivery systems and scaffolds for soft tissue engineering applications. The optimized synthesis and characterization of calcium-containing MCM-41 particles are reported. Homogeneous bead-free composite electrospun mats were obtained by using acetic acid and formic acid as solvents; neat PCL electrospun mats were used as control. Initially, an optimization of the electrospinning environmental parameters, like relative humidity, was performed. The obtained composite nanofibers were characterized from the morphological, chemical and mechanical points of view, the acellular bioactivity of the composite nanofibers was also investigated. Positive results were obtained in terms of mesoporous particle incorporation in the fibers and no significant differences in terms of average fiber diameter were detected between the neat and composite electrospun fibers. Even if the Ca-containing MCM-41 particles are bioactive, this property is not preserved in the composite fibers. In fact, during the bioactivity assessment, the particles were released confirming the potential application of the composite fibers as a drug delivery system. Preliminary in vitro tests with bone marrow stromal cells were performed to investigate cell adhesion on the fabricated composite mats, the positive obtained results confirmed the suitability of the composite fibers as scaffolds for soft tissue engineering.

  12. Fabrication and durable antibacterial properties of 3D porous wet electrospun RCSC/PCL nanofibrous scaffold with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Mei; Lin, Han [Alan G. MacDiarmid Laboratory, College of Chemistry, Jilin University, Changchun 130012 (China); Wang, Yilong [College of Quartermaster Technology, Jilin University, Changchun, 130062 (China); Yang, Guang [Norman Bethune First Hospital, Jilin University, Changchun 130021 (China); Zhao, He [Alan G. MacDiarmid Laboratory, College of Chemistry, Jilin University, Changchun 130012 (China); Sun, Dahui, E-mail: sundahui1971@sina.com [Norman Bethune First Hospital, Jilin University, Changchun 130021 (China)

    2017-08-31

    Highlights: • Ranachensinensis skin collagen (RCSC) was used with molecular weight 105∼250KDa. • Wet electrospinning was successfully improved and was used to produce 3D porous structure materials with about 90% porosity. • AgNPs was loaded in AgNPs dispersion liquid. - Abstract: Electrospunnanofibers are used as three-dimensional (3D) scaffold materials that can alter cell attachment and cell proliferation, change the antibacterial properties of materials, and can be used as wound dressings. But the fabrication of porous 3D scaffold structure and the antibacterial properties enhancing are challenges remained to improve. With the states here, a Ranachensinensis skin collagen (RCSC)/poly(ε-caprolactone) (PCL)AgNP-loaded3D nanofiber scaffold is fabricated as a wound dressing material by using an improved wet electrospinning method (blending). The nanoscale of the AgNPs is proved. The 3D porous morphologies of the materials with different AgNP loadings, are determined with field emission scanning electron microscopy (FESEM) and the presence and uniformity distribution of AgNPs is confirmed by Energy dispersive X-ray (EDX) spectroscopy. The silver-ion release rates, antibacterial properties, and cytotoxicities of dressing materials with different AgNP contents are evaluated using ICP-AES, the zone inhibition method, and MTT testing. These results showed that the improved wet electrospun is an effective way to fabricate AgNP loaded 3D scaffold materials with porous structure and nearly 90% porosity and the presence of AgNPs in dressing materials strengthen the antibacterial properties. The RCSC/PCL 3D scaffold materials containing 2.0%AgNP would be promising for dressing materials application nearly without cytotoxicities.

  13. Efficient and Tumor Targeted siRNA Delivery by Polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol)-folate (PEI-PCL-PEG-Fol).

    Science.gov (United States)

    Liu, Li; Zheng, Mengyao; Librizzi, Damiano; Renette, Thomas; Merkel, Olivia M; Kissel, Thomas

    2016-01-04

    Efficient delivery of functional nucleic acids into specific cells or tissues is still a challenge for gene therapy and largely depends on targeted delivery strategies. The folate receptor (FR) is known to be overexpressed extracellularly on a variety of human cancers and is therefore an outstanding gate for tumor-targeted Trojan horse-like delivery of therapeutics. In this study, an amphiphilic and biodegradable ternary copolymer conjugated with folate as ligand, polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol)-folate (PEI-PCL-PEG-Fol) was synthesized and evaluated for targeted siRNA delivery via folate-FR recognition. The amphiphilic character of similar polymers was shown previously to support endosomal release of endocytosed nanocarriers and to promote formation of long circulating micelles. The obtained PEI-PCL-PEG-Fol exhibited less cytotoxicity in comparison with the corresponding ternary copolymer without folate (PEI-PCL-PEG) and with unmodified PEI25kDa. Stable micelle-like polyplexes with hydrodynamic diameters about 100 nm were found to have a zeta potential of +8.6 mV, which was lower than that of micelleplexes without folate-conjugation (+13-16 mV). Nonetheless, increased cellular uptake and in vitro gene knockdown of PEI-PCL-PEG-Fol/siRNA micelleplexes were observed in SKOV-3 cells, an FR overexpressing cell line, in comparison with the nonfolate-conjugated ones. Moreover, PEI-PCL-PEG-Fol/siRNA micelleplexes exhibited excellent stability in vivo during the analysis of 120 min and a longer circulation half life than hyPEI25kDa/siRNA polyplexes. Most interestingly, the targeted delivery system yielded 17% deposition of the i.v. injected siRNA per gram in the tumor after 24 h due to the effective folate targeting and the prolonged circulation.

  14. Development of Emu oil-loaded PCL/collagen bioactive nanofibers for proliferation and stemness preservation of human adipose-derived stem cells: possible application in regenerative medicine.

    Science.gov (United States)

    Nejati-Koshki, Kazem; Pilehvar-Soltanahmadi, Younes; Alizadeh, Effat; Ebrahimi-Kalan, Abbas; Mortazavi, Yousef; Zarghami, Nosratollah

    2017-12-01

    Adipose tissue-derived stem cells (ASCs) are promising candidate in stem cell therapies, and maintaining their stemness potential is vital to achieve effective treatment. Natural-based scaffolds have been recently attracted increasing attention in nanomedicine and drug delivery. In the present study, a polymeric nanofibrous scaffold was developed based on the polycaprolactone/Collagen (PCL/Coll) containing Emu oil as a bioactive material to induce the proliferation of ASCs, while simultaneously preserving the stemness property of those cells. Fabrication of the electrospun Emu oil-loaded PCL/Coll nanofibers was confirmed by using FE-SEM, FTIR, and tensile test. ASCs were seeded on two types of nanofibers (PCL/Coll and Emu oil-loaded PCL/Coll) and their proliferation, cell cycle progression, and stemness gene expressions were evaluated using MTT, propidium iodide staining, and qPCR during 14 days, respectively. The results indicated that ASCs displayed improved adhesion capacity with the higher rates of bioactivity and proliferation on the Emu oil-loaded nanofibers than the other groups. The proliferation capacity of ASCs on Emu oil-loaded PCL/Coll nanofibers was further confirmed by the cell cycle progression analysis. It was also found that Emu oil-loaded nanofibers significantly up-regulated the expression of stemness markers including sox-2, nanog, oct4, klf4, and c-Myc. The results demonstrated that the nanofibers containing Emu oil can reinforce the cell adhesion and enhance ASCs proliferation while preserving their stemness; therefore, using scaffolds containing natural products may have a great potential to enhance the in vitro expansion capacity of ASCs in the field of stem cell therapy and regenerative medicine.

  15. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  16. Reverse Core Engine with Thrust Reverser

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

  17. Myocardial reverse remodeling.

    Science.gov (United States)

    Hellawell, Jennifer L; Margulies, Kenneth B

    2012-06-01

    Despite an extensive literature defining the mechanisms and significance of pathological myocardial remodeling, there has been no comprehensive review of the inverse process, often labeled reverse remodeling. Accordingly, the goal of this review is to overview the varied settings in which clinically significant reverse remodeling has been well documented. When available, we reviewed relevant randomized, controlled clinical trials, and meta-analyses with sufficient cardiac imaging data to permit conclusions about reverse remodeling. When these types of studies were not available, relevant case-control studies and case series that employed appropriate methodology were reviewed. Regression of pathological myocardial hypertrophy, chamber shape distortions, and dysfunction occurs in a wide variety of settings. Although reverse remodeling occurs spontaneously in some etiologies of myocardial dysfunction and failure, remodeling is more commonly observed in response to medical, device-based, or surgical therapies, including β-blockers, revascularization, cardiac resynchronization therapy, and valve surgery. Indeed, reverse remodeling following pathophysiologically targeted interventions helps validate that the targeted mechanisms are propelling and/or sustaining pathological remodeling. The diverse clinical settings in which reverse remodeling has been observed demonstrates that myocardial remodeling is bidirectional and occurs across the full spectrum of myocardial disease severity, duration, and etiology. Observations in several settings suggest that recovered hearts are not truly normal despite parallel improvements at organ, tissue, and cellular level. Nevertheless, the link between reverse remodeling and improved outcomes should inspire further research to better understand the mechanisms responsible for both reverse remodeling and persistent deviations from normalcy. © 2010 Blackwell Publishing Ltd.

  18. A CONTRASTIVE ANALYSIS OF THE FACTORIAL STRUCTURE OF THE PCL-R: WHICH MODEL FITS BEST THE DATA?

    Directory of Open Access Journals (Sweden)

    Beatriz Pérez

    2015-01-01

    Full Text Available The aim of this study was to determine which of the factorial solutions proposed for the Hare Psychopathy Checklist-Revised (PCL-R of two, three, four factors, and unidimensional fitted best the data. Two trained and experienced independent raters scored 197 prisoners from the Villabona Penitentiary (Asturias, Spain, age range 21 to 73 years (M = 36.0, SD = 9.7, of whom 60.12% were reoffenders and 73% had committed violent crimes. The results revealed that the two-factor correlational, three-factor hierarchical without testlets, four-factor correlational and hierarchical, and unidimensional models were a poor fit for the data (CFI ≤ .86, and the three-factor model with testlets was a reasonable fit for the data (CFI = .93. The scale resulting from the three-factor hierarchical model with testlets (13 items classified psychopathy significantly higher than the original 20-item scale. The results are discussed in terms of their implications for theoretical models of psychopathy, decision-making, prison classification and intervention, and prevention. Se diseñó un estudio con el objetivo de conocer cuál de las soluciones factoriales propuestas para la Hare Psychopathy Checklist-Revised (PCL-R de dos, tres y cuatro factores y unidimensional era la que presentaba mejor ajuste a los datos. Para ello, dos evaluadores entrenados y con experiencia evaluaron de forma independiente a 197 internos en la prisión Villabona (Asturias, España, con edades comprendidas entre los 21 y los 73 años (M = 36.0, DT = 9.7, de los cuales el 60.12% eran reincidentes y el 73% había cometido delitos violentos. Los resultados mostraron que los modelos unidimensional, correlacional de 2 factores, jerárquico de 3 factores sin testlest y correlacional y jerárquico de 4 factores, presentaban un pobre ajuste con los datos (CFI ≤ .86 y un ajuste razonable del modelo jerárquico de tres factores con testlets (CFI = .93. La escala resultante del modelo de tres factores

  19. Double inflation

    Energy Technology Data Exchange (ETDEWEB)

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The ..cap omega..-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig.

  20. Seeing Double

    Science.gov (United States)

    Pesic, Peter

    2003-10-01

    The separateness and connection of individuals is perhaps the central question of human life: What, exactly, is my individuality? To what degree is it unique? To what degree can it be shared, and how? To the many philosophical and literary speculations about these topics over time, modern science has added the curious twist of quantum theory, which requires that the elementary particles of which everything consists have no individuality at all. All aspects of chemistry depend on this lack of individuality, as do many branches of physics. From where, then, does our individuality come? In Seeing Double, Peter Pesic invites readers to explore this intriguing set of questions. He draws on literary and historical examples that open the mind (from Homer to Martin Guerre to Kafka), philosophical analyses that have helped to make our thinking and speech more precise, and scientific work that has enabled us to characterize the phenomena of nature. Though he does not try to be all-inclusive, Pesic presents a broad range of ideas, building toward a specific point of view: that the crux of modern quantum theory is its clash with our ordinary concept of individuality. This represents a departure from the usual understanding of quantum theory. Pesic argues that what is bizarre about quantum theory becomes more intelligible as we reconsider what we mean by individuality and identity in ordinary experience. In turn, quantum identity opens a new perspective on us. Peter Pesic is a Tutor and Musician-in-Residence at St. John's College, Santa Fe, New Mexico. He has a Ph.D. in physics from Stanford University.

  1. Enhancing the Hydrophilicity and Cell Attachment of 3D Printed PCL/Graphene Scaffolds for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Weiguang Wang

    2016-12-01

    Full Text Available Scaffolds are physical substrates for cell attachment, proliferation, and differentiation, ultimately leading to the regeneration of tissues. They must be designed according to specific biomechanical requirements, i.e., certain standards in terms of mechanical properties, surface characteristics, porosity, degradability, and biocompatibility. The optimal design of a scaffold for a specific tissue strongly depends on both materials and manufacturing processes, as well as surface treatment. Polymeric scaffolds reinforced with electro-active particles could play a key role in tissue engineering by modulating cell proliferation and differentiation. This paper investigates the use of an extrusion-based additive manufacturing system to produce poly(ε-caprolactone (PCL/pristine graphene scaffolds for bone tissue applications and the influence of chemical surface modification on their biological behaviour. Scaffolds with the same architecture but different concentrations of pristine graphene were evaluated from surface property and biological points of view. Results show that the addition of pristine graphene had a positive impact on cell viability and proliferation, and that surface modification leads to improved cell response.

  2. Enhancing the Hydrophilicity and Cell Attachment of 3D Printed PCL/Graphene Scaffolds for Bone Tissue Engineering.

    Science.gov (United States)

    Wang, Weiguang; Caetano, Guilherme; Ambler, William Stephen; Blaker, Jonny James; Frade, Marco Andrey; Mandal, Parthasarathi; Diver, Carl; Bártolo, Paulo

    2016-12-07

    Scaffolds are physical substrates for cell attachment, proliferation, and differentiation, ultimately leading to the regeneration of tissues. They must be designed according to specific biomechanical requirements, i.e., certain standards in terms of mechanical properties, surface characteristics, porosity, degradability, and biocompatibility. The optimal design of a scaffold for a specific tissue strongly depends on both materials and manufacturing processes, as well as surface treatment. Polymeric scaffolds reinforced with electro-active particles could play a key role in tissue engineering by modulating cell proliferation and differentiation. This paper investigates the use of an extrusion-based additive manufacturing system to produce poly(ε-caprolactone) (PCL)/pristine graphene scaffolds for bone tissue applications and the influence of chemical surface modification on their biological behaviour. Scaffolds with the same architecture but different concentrations of pristine graphene were evaluated from surface property and biological points of view. Results show that the addition of pristine graphene had a positive impact on cell viability and proliferation, and that surface modification leads to improved cell response.

  3. Synthesis and characterization of the antitubercular phenazine lapazine and development of PLGA and PCL nanoparticles for its entrapment.

    Science.gov (United States)

    Silveira, Narjara; Longuinho, Mariana M; Leitão, Suzana G; Silva, Raphael S F; Lourenço, Maria C; Silva, Pedro E A; Pinto, Maria do Carmo F R; Abraçado, Leida G; Finotelli, Priscilla V

    2016-01-01

    The aim of this work was to develop and characterize nanoparticles as carriers of lapazine, a phenazine derived from β-lapachone; its antimycobacterial activity is described for the first time as a potential treatment for tuberculosis. The lapazine was synthesized, and by using gas chromatography coupled to a flame ionization detector, it was possible to evaluate its purity degree of almost 100%. For better elucidation of the molecular structure, mass spectroscopy and 1H NMR were carried out and compared to the literature values. Lapazine was assayed in vitro against H37Rv Mycobacterium tuberculosis and a rifampicin-resistant strain, with minimum inhibitory concentration values of 3.00 and 1.56 μg mL(-1), respectively. The nanoparticles showed a polydispersity index of 0.16,mean diameter of 188.5 ± 1.7 mm, zeta potential of -15.03 mV, and drug loading of 54.71 mg g(-1) for poly-ε-caprolactone (PCL) nanoparticles and a polydispersity index of 0.318,mean diameter of 197.4 ± 2.7 mm, zeta potential of -13.43 mV and drug loading of 137.07 mg g(-1) for poly(DL-lactide-co-glycolide) (PLGA) nanoparticles. These results indicate that both polymeric formulations have good characteristics as potential lapazine carriers in the treatment of tuberculosis.

  4. Scaffolds from block polyurethanes based on poly(ɛ-caprolactone) (PCL) and poly(ethylene glycol) (PEG) for peripheral nerve regeneration.

    Science.gov (United States)

    Niu, Yuqing; Chen, Kevin C; He, Tao; Yu, Wenying; Huang, Shuiwen; Xu, Kaitian

    2014-05-01

    Nerve guide scaffolds from block polyurethanes without any additional growth factors or protein were prepared using a particle leaching method. The scaffolds of block polyurethanes (abbreviated as PUCL-ran-EG) based on poly(ɛ-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) possess highly surface-area porous for cell attachment, and can provide biochemical and topographic cues to enhance tissue regeneration. The nerve guide scaffolds have pore size 1-5 μm and porosity 88%. Mechanical tests showed that the polyurethane nerve guide scaffolds have maximum loads of 4.98 ± 0.35 N and maximum stresses of 6.372 ± 0.5 MPa. The histocompatibility efficacy of these nerve guide scaffolds was tested in a rat model for peripheral nerve injury treatment. Four types of guides including PUCL-ran-EG scaffolds, autograft, PCL scaffolds and silicone tubes were compared in the rat model. After 14 weeks, bridging of a 10 mm defect gap by the regenerated nerve was observed in all rats. The nerve regeneration was systematically characterized by sciatic function index (SFI), histological assessment including HE staining, immunohistochemistry, ammonia silver staining, Masson's trichrome staining and TEM observation. Results revealed that polyurethane nerve guide scaffolds exhibit much better regeneration behavior than PCL, silicone tube groups and comparable to autograft. Electrophysiological recovery was also seen in 36%, 76%, and 87% of rats in the PCL, PUCL-ran-EG, and autograft groups respectively, whilst 29.8% was observed in the silicone tube groups. Biodegradation in vitro and in vivo show proper degradation of the PUCL-ran-EG nerve guide scaffolds. This study has demonstrated that without further modification, plain PUCL-ran-EG nerve guide scaffolds can help peripheral nerve regeneration excellently. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The Influence of Lyophilized EmuGel Silica Microspheres on the Physicomechanical Properties, In Vitro Bioactivity and Biodegradation of a Novel Ciprofloxacin-Loaded PCL/PAA Scaffold

    Directory of Open Access Journals (Sweden)

    Mostafa Mabrouk

    2016-06-01

    Full Text Available A new composite poly(caprolactone (PCL and poly(acrylic acid (PAA (PCL:PAA 1:5 scaffold was synthesized via dispersion of PCL particles into a PAA network. Silica microspheres (Si (2–12 μm were then prepared by a lyophilized micro-emulsion/sol-gel (Emugel system using varying weight ratios. The model drug ciprofloxacin (CFX was used for in situ incorporation into the scaffold. The physicochemical and thermal integrity, morphology and porosity of the system was analyzed by X-Ray Diffraction (XRD, Attenuated Total Refelctance Fourier Transform Infrared (ATR-FTIR, Differential Scanning Calorimetry (DSC, SEM, surface area analysis and liquid displacement, respectively. The mechanical properties of the scaffold were measured by textural analysis and in vitro bioactivity, biodegradation and pH variations were evaluated by XRD, FTIR and SEM after immersion in Simulated Body Fluid (SBF. The in vitro and in vivo studies of the prepared scaffold were considered as future aspects for this study. CFX release was determined in phosphate buffer saline (PBS (pH 7.4; 37 °C. The incorporation of the Si microspheres and CFX into the scaffold was confirmed by XRD, FTIR, DSC and SEM, and the scaffold microstructure was dependent on the concentration of Si microspheres and the presence of CFX. The system displayed enhanced mechanical properties (4.5–14.73 MPa, in vitro bioactivity, biodegradation and controlled CFX release. Therefore, the PCL/PAA scaffolds loaded with Si microspheres and CFX with a porosity of up to 87% may be promising for bone tissue engineering.

  6. Direct oral anticoagulant reversal

    DEFF Research Database (Denmark)

    Dzeshka, Mikhail S; Pastori, Daniele; Lip, Gregory Y H

    2017-01-01

    to manage bleeding depending on severity, with a particular focus on specific reversal agents, are discussed. Expert commentary: Due to short half-life of NOACs compared to warfarin, discontinuation of drug, mechanical compression, and volume substitution are considered to be sufficient measures in most...... of bleeding cases. In case of life-threatening bleeding or urgent surgery, hemostasis can be achieved with non-specific reversal agents (prothrombin complex concentrates) in patients treated with factor Xa inhibitor until specific antidotes (andexanet α and ciraparantag) will receive approval. Thus far......, idarucizumab has been the only reversal agent approved for dabigatran....

  7. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  8. Double hard scattering without double counting

    Science.gov (United States)

    Diehl, Markus; Gaunt, Jonathan R.; Schönwald, Kay

    2017-06-01

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  9. Double hard scattering without double counting

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2017-02-15

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  10. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cuong, Nguyen-Van [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Department of Chemical Engineering, Ho Chi Minh City University of Industry, 12 Nguyen Van Bao St, Ho Chi Minh (Viet Nam); Jiang, Jian-Lin; Li, Yu-Lun [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Chen, Jim-Ray [Department of Pathology, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Jwo, Shyh-Chuan [Division of General Surgery, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Hsieh, Ming-Fa, E-mail: mfhsieh@cycu.edu.tw [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China)

    2010-12-28

    The triblock copolymer is composed of two identical hydrophilic segments Monomethoxy poly(ethylene glycol) (mPEG) and one hydrophobic segment poly(ε-caprolactone) (PCL); which is synthesized by coupling of mPEG-PCL-OH and mPEG-COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX) in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo) showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14) of DOX-loaded micelles as compared to multiple administrations of free DOX.

  11. Environmentally Friendly Compatibilizers from Soybean Oil for Ternary Blends of Poly(lactic acid)-PLA, Poly(ε-caprolactone)-PCL and Poly(3-hydroxybutyrate)-PHB.

    Science.gov (United States)

    Garcia-Campo, María Jesús; Quiles-Carrillo, Luis; Masia, Jaime; Reig-Pérez, Miguel Jorge; Montanes, Nestor; Balart, Rafael

    2017-11-22

    Ternary blends of poly(lactic acid) (PLA), poly(3-hydroxybutyrate) (PHB) and poly(ε-caprolactone) (PCL) with a constant weight percentage of 60%, 10% and 30% respectively were compatibilized with soybean oil derivatives epoxidized soybean oil (ESO), maleinized soybean oil (MSO) and acrylated epoxidized soybean oil (AESO). The potential compatibilization effects of the soybean oil-derivatives was characterized in terms of mechanical, thermal and thermomechanical properties. The effects on morphology were studied by field emission scanning electron microscopy (FESEM). All three soybean oil-based compatibilizers led to a noticeable increase in toughness with a remarkable improvement in elongation at break. On the other hand, both the tensile modulus and strength decreased, but in a lower extent to a typical plasticization effect. Although phase separation occurred, all three soybean oil derivatives led somewhat to compatibilization through reaction between terminal hydroxyl groups in all three biopolyesters (PLA, PHB and PCL) and the readily reactive groups in the soybean oil derivatives, that is, epoxy, maleic anhydride and acrylic/epoxy functionalities. In particular, the addition of 5 parts per hundred parts of the blend (phr) of ESO gave the maximum elongation at break while the same amount of MSO and AESO gave the maximum toughness, measured through Charpy's impact tests. In general, the herein-developed materials widen the potential of ternary PLA formulations by a cost effective blending method with PHB and PCL and compatibilization with vegetable oil-based additives.

  12. Nanocapsules based on linear and Y-shaped 3-miktoarm star-block PEO-PCL copolymers as sustained delivery system for hydrophilic molecules.

    Science.gov (United States)

    Maglio, Giovanni; Nicodemi, Fabio; Conte, Claudia; Palumbo, Rosario; Tirino, Pasquale; Panza, Elisabetta; Ianaro, Angela; Ungaro, Francesca; Quaglia, Fabiana

    2011-12-12

    Well-defined amphiphilic Y-shaped miktoarm star-block copolymers of PEO and PCL were synthesized by ring-opening polymerization of ε-caprolactone initiated by a PEO-bound lysine macroinitiator. The copolymers were characterized by (1)H NMR, SEC, DSC, and WAXD techniques. Separate PCL and PEO crystalline phases occur in melt-crystallized copolymers when their segmental lengths were comparable and the PCL content was ≤80 wt %. Self-assembling of these copolymers in aqueous medium led to nanoaggregates with low critical aggregation concentration values (0.35 to 1.6 mg·L(-1)) and size depending on composition. Despite the fact that copolymers were not prone to self-organize in vesicles, once processed by a novel w/o emulsion-melting-sonication technique, they gave nanocapsules with a water core and a hydrophilic surface. A macromolecular fluorescent dye was effectively loaded and released at sustained rate by optimizing nanocapsule formulation. The results demonstrate that amphiphilic block copolymers can be assembled in different kinds of nanomorphologies independently of their hydrophilic/hydrophobic balance and architecture through specifically designed preparation techniques.

  13. Personality traits as predictors of inpatient aggression in a high-security forensic psychiatric setting: prospective evaluation of the PCL-R and IPDE dimension ratings.

    Science.gov (United States)

    Langton, Calvin M; Hogue, Todd E; Daffern, Michael; Mannion, Aisling; Howells, Kevin

    2011-05-01

    The Dangerous and Severe Personality Disorder (DSPD) initiative in England and Wales provides specialized care to high-risk offenders with mental disorders. This study investigated the predictive utility of personality traits, assessed using the Psychopathy Checklist-Revised (PCL-R) and the International Personality Disorder Examination, with 44 consecutive admissions to the DSPD unit at a high-security forensic psychiatric hospital. Incidents of interpersonal physical aggression (IPA) were observed for 39% of the sample over an average 1.5-year period following admission. Histrionic personality disorder (PD) predicted IPA, and Histrionic, Borderline, and Antisocial PDs all predicted repetitive (2+ incidents of) IPA. PCL-R Factor 1 and Facets 1 and 2 were also significant predictors of IPA. PCL-R Factor 1 and Histrionic PD scores were significantly associated with imminence of IPA. Results were discussed in terms of the utility of personality traits in risk assessment and treatment of specially selected high-risk forensic psychiatric patients in secure settings.

  14. Synthesis and self-assembly behavior of amphiphilic diblock copolymer dextran-block-poly(ε-caprolactone (DEX-b-PCL in aqueous media

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available An amphiphilic diblock copolymer, dextran-block-poly(ε-caprolactone (DEX-b-PCL, with a series of welldefined chain lengths of each block was prepared by conjugating a dextran chain with a PCL block via aza-Michael addition reaction under mild conditions. For the dextran block, samples with relatively uniform molecular weight, 3.5 and 6.0 kDa, were used, and the PCL blocks were prepared via ring-opening polymerization at defined ratios of ε-caprolactone to initiator in order to give copolymers with mass fraction of dextran (fDEX ranging from 0.16 to 0.45. When these copolymers were allowed to self-assemble in aqueous solution, the morphology of assembled aggregates varied as a function of fDEX when characterized by transmission electron microscope (TEM, fluorescence microscope (FM and dynamic laser scattering (DLS. As fDEX decreases gradually from 0.45 to 0.16, the morphology of the copolymer assembly changes from spherical micelles to worm-like micelles and eventually to polymersomes, together with an increase in particle sizes.

  15. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Directory of Open Access Journals (Sweden)

    Ming-Fa Hsieh

    2010-12-01

    Full Text Available The triblock copolymer is composed of two identical hydrophilic segments: Monomethoxy poly(ethylene glycol (mPEG and one hydrophobic segment poly(ε‑caprolactone (PCL; which is synthesized by coupling of mPEG-PCL-OH and mPEG‑COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14 of DOX-loaded micelles as compared to multiple administrations of free DOX.

  16. Environmentally Friendly Compatibilizers from Soybean Oil for Ternary Blends of Poly(lactic acid-PLA, Poly(ε-caprolactone-PCL and Poly(3-hydroxybutyrate-PHB

    Directory of Open Access Journals (Sweden)

    María Jesús Garcia-Campo

    2017-11-01

    Full Text Available Ternary blends of poly(lactic acid (PLA, poly(3-hydroxybutyrate (PHB and poly(ε-caprolactone (PCL with a constant weight percentage of 60%, 10% and 30% respectively were compatibilized with soybean oil derivatives epoxidized soybean oil (ESO, maleinized soybean oil (MSO and acrylated epoxidized soybean oil (AESO. The potential compatibilization effects of the soybean oil-derivatives was characterized in terms of mechanical, thermal and thermomechanical properties. The effects on morphology were studied by field emission scanning electron microscopy (FESEM. All three soybean oil-based compatibilizers led to a noticeable increase in toughness with a remarkable improvement in elongation at break. On the other hand, both the tensile modulus and strength decreased, but in a lower extent to a typical plasticization effect. Although phase separation occurred, all three soybean oil derivatives led somewhat to compatibilization through reaction between terminal hydroxyl groups in all three biopolyesters (PLA, PHB and PCL and the readily reactive groups in the soybean oil derivatives, that is, epoxy, maleic anhydride and acrylic/epoxy functionalities. In particular, the addition of 5 parts per hundred parts of the blend (phr of ESO gave the maximum elongation at break while the same amount of MSO and AESO gave the maximum toughness, measured through Charpy’s impact tests. In general, the herein-developed materials widen the potential of ternary PLA formulations by a cost effective blending method with PHB and PCL and compatibilization with vegetable oil-based additives.

  17. The validity of military screening for mental health problems: diagnostic accuracy of the PCL, K10 and AUDIT scales in an entire military population.

    Science.gov (United States)

    Searle, Amelia K; Van Hooff, Miranda; McFarlane, Alexander C; Davies, Christopher E; Fairweather-Schmidt, A Kate; Hodson, Stephanie E; Benassi, Helen; Steele, Nicole

    2015-03-01

    Depression, alcohol use disorders and post-traumatic stress disorder (PTSD) are serious issues among military personnel due to their impact on operational capability and individual well-being. Several military forces screen for these disorders using scales including the Kessler Psychological Distress Scale (K10), Alcohol Use Disorders Identification Test (AUDIT), and Post-traumatic Stress Disorder Checklist (PCL). However, it is unknown whether established cutoffs apply to military populations. This study is the first to test the diagnostic accuracy of these three scales in a population-based military cohort. A large sample of currently-serving Australian Defence Force (ADF) Navy, Army and Air Force personnel (n = 24,481) completed the K10, AUDIT and PCL-C (civilian version). Then, a stratified sub-sample (n = 1798) completed a structured diagnostic interview detecting 30-day disorder. Data were weighted to represent the ADF population (n = 50,049). Receiver operating characteristic (ROC) analyses suggested all three scales had acceptable sensitivity and specificity, with areas under the curve from 0.75 to 0.93. AUDIT and K10 screening cutoffs closely paralleled established cutoffs, whereas the PCL-C screening cutoff resembled that recommended for US military personnel. These self-report scales represent a cost-effective and clinically-useful means of screening personnel for disorder. Military populations may need lower cutoffs than civilians to screen for PTSD. Copyright © 2014 John Wiley & Sons, Ltd.

  18. Optimizing the value of the posterior condylar offset, proximal tibial resection and slope in order to achieve the right balance of the posterior cruciate ligament - clinical application of the molding function of the two parts of the PCL

    Science.gov (United States)

    Bogojevski, Ljubomir; Doksevska, Milena Bogojevska

    2017-01-01

    Introduction: In order to achieve the right balance of the posterior cruciate ligament using the skeletal method is very difficult, almost impossible (Mahoney). Our hypothesis for the right balance of the PCL by using the skeletal method is based on several defined facts: - PCL is a union based of two anatomically independent, but functionally synergic parts, posteromedial and anterolateral part. - The length of the posteromedial part of the PCL is determined by the belonging of the medial compartment and is shortest in varus and longest in valgus deformation. - The length of the anterolateral part of the PCL, placed centrally is unchangeable (cca 38 mm) in every knee and is independent from the anatomical appearance (deformation). - The cylindrical shape of the distal posterior part of the femur (Ficat) depends of the molding function of the PCL (Kapandji) and is a result of the proportion of the both parts of the PCL that is consisted of: shorter posteromedial part, less bone stock on the medial and more bone stock on the lateral condyle (varus knee) and vice versa, longer posteromedial part, more bone stock on the medial condyle and less on the lateral (valgus knee). According to that, the neutral bone stock is achieved by equalization of the lengths of the two parts (common radius of the cylinder) of the PCL, that is basis for the interligamentary balance of the posterior cruciate ligament. Methods: The basic characteristics of the interligamentary balance of the PCL that we started in 2008 are the following: 1. Posterior condylar offset is equal to the even length of the both part of the PCL. 2. Decrease of the values of proximal tibial resection from 10 in varus to 4-6 in valgus. 3. Femoral valgus cut from 6 in excessive varus deformity to 4 in valgus. Results: The clinical evaluation of the cases divided in groups excessive varus, mean varus, valgus type 1, 2 (Krakow) showed right distribution in the groups of the postoperative ROM and intraoperative

  19. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow o...... justification for low-level machine code for reversible microprocessors as well as high-level block-structured reversible languages. We give examples for both such languages and illustrate them with a lossless encoder for permutations given by Dijkstra....

  20. Tubal Ligation Reversal

    Science.gov (United States)

    ... and other factors. Success rates may be as high as 80 percent or as low as near 40 percent depending on your circumstances. Tubal ligation reversal is abdominal surgery, which carries a risk of infection, bleeding and ...

  1. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  2. PROCESSING REVERSE LOGISTICS INVENTORIES

    OpenAIRE

    Bajor, Ivona; Novačko, Luka; Ogrizović, Dario

    2014-01-01

    Developed logistics systems have organized reverse logistics flows and are continuously analyzing product returns, tending to detect patterns in oscillations of returning products in certain time periods. Inventory management in reverse logistics systems depends on different criteria, regarding goods categories, formed contracts between subjects of supply chains, uncertainty in manufacturer’s quantities of DOA (dead on arrival) products, etc. The developing logistics systems, such as the Croa...

  3. Nanoencapsulation of water-soluble drug, lamivudine, using a double emulsion spray-drying technique for improving HIV treatment

    Science.gov (United States)

    Tshweu, Lesego; Katata, Lebogang; Kalombo, Lonji; Swai, Hulda

    2013-11-01

    Current treatments available for human immunodeficiency virus, namely antiretrovirals, do not completely eradicate the virus from the body, leading to life-time commitment. Many antiretrovirals suffer drawbacks from toxicity and unpleasant side effects, causing patience non-compliance. To minimize challenges associated with the antiretrovirals, biodegradable nanoparticles used as drug delivery systems hold tremendous potential to enhance patience compliance. The main objective of this work was to load lamivudine (LAM) into poly(epsilon-caprolactone) (PCL) nanoparticles. LAM is a hydrophilic drug with low plasma half-life of 5-7 h and several unpleasant side effects. LAM was nanoencapsulated into PCL polymer via the double emulsion spray-drying method. Formulation parameters such as the effect of solvent, excipient and drug concentration were optimized for the synthesis of the nanoparticles. Spherical nanoparticles with an average size of 215 ± 3 nm and polydispersity index (PDI) of 0.227 ± 0.01 were obtained, when ethyl acetate and lactose were used in the preparation. However, dichloromethane presented sizes larger than 454 ± 11 nm with PDI of more than 0.4 ± 0.05, irrespective of whether lactose or trehalose was used in the preparation. Some of the nanoparticles prepared with trehalose resulted in crystal formation. UV spectroscopy showed encapsulation efficiency ranging from 68 ± 4 to 78 ± 4 % for LAM depending on the starting drug concentration. Fourier transform infrared spectroscopy and X-ray diffraction confirmed the possibility of preparing amorphous PCL nanoparticles containing LAM. Drug release extended for 4 days in pH 1.3, pH 4.5 and pH 6.8. These results indicated that LAM-loaded PCL nanoparticles show promise for controlled delivery.

  4. Nanoencapsulation of water-soluble drug, lamivudine, using a double emulsion spray-drying technique for improving HIV treatment

    Energy Technology Data Exchange (ETDEWEB)

    Tshweu, Lesego, E-mail: tshweull@gmail.com [Council for Scientific and Industrial Research, Materials Science and Manufacturing, Polymers and Composites (South Africa); Katata, Lebogang [North West University, Chemistry Department, Faculty of Agriculture, Science and Technology (South Africa); Kalombo, Lonji; Swai, Hulda [Council for Scientific and Industrial Research, Materials Science and Manufacturing, Polymers and Composites (South Africa)

    2013-11-15

    Current treatments available for human immunodeficiency virus, namely antiretrovirals, do not completely eradicate the virus from the body, leading to life-time commitment. Many antiretrovirals suffer drawbacks from toxicity and unpleasant side effects, causing patience non-compliance. To minimize challenges associated with the antiretrovirals, biodegradable nanoparticles used as drug delivery systems hold tremendous potential to enhance patience compliance. The main objective of this work was to load lamivudine (LAM) into poly(epsilon-caprolactone) (PCL) nanoparticles. LAM is a hydrophilic drug with low plasma half-life of 5–7 h and several unpleasant side effects. LAM was nanoencapsulated into PCL polymer via the double emulsion spray-drying method. Formulation parameters such as the effect of solvent, excipient and drug concentration were optimized for the synthesis of the nanoparticles. Spherical nanoparticles with an average size of 215 ± 3 nm and polydispersity index (PDI) of 0.227 ± 0.01 were obtained, when ethyl acetate and lactose were used in the preparation. However, dichloromethane presented sizes larger than 454 ± 11 nm with PDI of more than 0.4 ± 0.05, irrespective of whether lactose or trehalose was used in the preparation. Some of the nanoparticles prepared with trehalose resulted in crystal formation. UV spectroscopy showed encapsulation efficiency ranging from 68 ± 4 to 78 ± 4 % for LAM depending on the starting drug concentration. Fourier transform infrared spectroscopy and X-ray diffraction confirmed the possibility of preparing amorphous PCL nanoparticles containing LAM. Drug release extended for 4 days in pH 1.3, pH 4.5 and pH 6.8. These results indicated that LAM-loaded PCL nanoparticles show promise for controlled delivery.

  5. Optimized 4-bit Quantum Reversible Arithmetic Logic Unit

    Science.gov (United States)

    Ayyoub, Slimani; Achour, Benslama

    2017-08-01

    Reversible logic has received a great attention in the recent years due to its ability to reduce the power dissipation. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. The arithmetic logic unit (ALU) is an important part of central processing unit (CPU) as the execution unit. This paper presents a complete design of a new reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The proposed ALU based on a reversible low power control unit and small performance parameters full adder named double Peres gates. The presented ALU can produce the largest number (28) of arithmetic and logic functions and have the smallest number of quantum cost and delay compared with existing designs.

  6. PCL foamed scaffolds loaded with 5-fluorouracil anti-cancer drug prepared by an eco-friendly route.

    Science.gov (United States)

    Salerno, Aurelio; Domingo, Concepción; Saurina, Javier

    2017-06-01

    This study describes a new preparation method, which combines freeze drying and supercritical CO2 foaming approaches, for the preparation of drug delivery scaffolds of polycaprolactone loaded with 5-fluorouracil, an anti-cancer drug, with low solubility in scCO2. It is a principal objective of this work to design a scCO2 strategy to reduce 5-Fu solubility limitations in its homogeneous distribution into a PCL scaffold through the design of an innovative processing method. The design of this process is considered valuable for the development of clean technology in pharmacy and medicine, since most of the active agents have a null solubility in scCO2·Supercritical CO2 is used as a blowing agent to induce polymer foaming by means of the low temperature pressure quench process. The resulting samples have been prepared under different operational conditions focused on enhancing the performance of the release process. In this case, design of experiments (DOE) was considered for a more comprehensive and systematic optimization of the product. In particular, drug amount, equals to 4.8 or 9.1wt%, process temperature, of 45 or 50°C and depressurization rate, equals to 0.1MPas(-1) or 2MPas(-1) were selected as the factors to be investigated by a three-factor at two-level full factorial design. Samples were characterized to establish porosity data, drug loading percentage and, especially, release profile chromatographically monitored. Results from DOE have concluded which are the best samples providing a sustained drug release for several days, which may be of great interest to develop materials for tissue engineering and sustained release applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Regiocontroll synthesis cellulose-graft-polycaprolactone copolymer (2,3-di-O-PCL-cellulose by a new route

    Directory of Open Access Journals (Sweden)

    K. L. Wang

    2017-12-01

    Full Text Available A new and convenient route to the regiocontrolled synthesis of a cellulose-based derivate copolymer (2,3-di-O-polycaprolactone-cellulose grafting ε-caprolactone (ε-CL from α-cellulose, cellulose-graft-polycaprolactone (cellulose-g-PCL, by a classical ring-opening polymerization (ROP reaction, using stannous octoate (Sn(Oct2 as catalyst, in 68% concentration of zinc chloride aqueous solution at 120 °C was presented. By controlling the hydroxyl of cellulose/ε-CL, catalyst/monomer ratio and the reaction time, the molecular architecture of the copolymers can be altered. The solubility of cellulose in zinc chloride aqueous was indicated by UV/VIS spectrometer and rheological measurements. The structures and thermal properties of cellulose-g-polycaprolactone copolymers were characterized using Fourier Transform Infrared (FT-IR, Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR, X-ray Diffraction (XRD, Thermogravimetric Analysis (TGA, Differential Scanning Calorimetry (DSC and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES. The interesting results confirm that zinc chloride solution can break the intra-molecular hydrogen bonds of cellulose selectively (not only O3H···O5, but also O2H···O6, and has no effect on the inter-molecular hydrogen bonds (O6H···O3. And the grafting reactivity of hydroxyl on cellulose is C2–OH > C3–OH >> C6–OH in zinc chloride solution, and this is clearly different from other researches. Most importantly, this work confirms that the method to regiocontrolled synthesis cellulose-based derivative polymers by regiobreaking hydrogen bonds is feasible. It is strongly believed that the new discovery may give a novel, environmental, simple and inexpensive method to modify cellulose chemically with various side chains grafted on a given hydroxyl, through liberating hydroxyl as reactive group from hydrogen bonds broken selectively by different solvents.

  8. Cell cycle checkpoints: reversible when possible, irreversible when needed

    NARCIS (Netherlands)

    Krenning, L.

    2015-01-01

    Cell cycle checkpoints are reversible in nature, and can prevent progression into the next cell cycle phase if needed. In the case of DNA damage, cells can prevent progression from G1 into S phase, and from G2 into mitosis in the presence of DNA double strand breaks. Following DNA repair, these

  9. Detection of viruses in seeds of some vegetables by reverse ...

    African Journals Online (AJOL)

    ... nutrition and seed production in Turkey. 50 seed samples for each vegetable obtained from various foundations and farmers were tested by reverse transcriptase polymerase chain reaction (RT-PCR) and double-antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) was conducted to compare the results.

  10. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  11. A randomized, double-blind, active-controlled phase 2 trial to evaluate a novel selective and reversible intravenous and oral P2Y12 inhibitor elinogrel versus clopidogrel in patients undergoing nonurgent percutaneous coronary intervention: the INNOVATE-PCI trial.

    Science.gov (United States)

    Welsh, Robert C; Rao, Sunil V; Zeymer, Uwe; Thompson, Vivian P; Huber, Kurt; Kochman, Janusz; McClure, Matthew W; Gretler, Daniel D; Bhatt, Deepak L; Gibson, C Michael; Angiolillo, Dominick J; Gurbel, Paul A; Berdan, Lisa G; Paynter, Gayle; Leonardi, Sergio; Madan, Mina; French, William J; Harrington, Robert A

    2012-06-01

    We evaluated the safety, efficacy, and tolerability of elinogrel, a competitive, reversible intravenous and oral P2Y(12) inhibitor that does not require metabolic activation, in patients undergoing nonurgent percutaneous coronary intervention. In a randomized, double-blind, dose-ranging phase 2b trial, 652 patients received either 300 or 600 mg of clopidogrel pre-percutaneous coronary intervention followed by 75 mg daily or 80 or 120 mg of IV elinogrel followed by 50, 100, or 150 mg oral elinogrel twice daily. Numerous exploratory safety and efficacy end points were assessed and, as such, had no prespecified primary end point, and the study was not powered to conclusively evaluate its objectives. Thrombolysis in myocardial infarction combined bleeding was increased with elinogrel (hazard ratio, 1.98; 95% confidence interval, 1.10 to 3.57), related largely to increased bleeding requiring medical attention (elinogrel 47/408 [11.5%] versus clopidogrel 13/208 [6.3%]) and occurring primarily at the percutaneous coronary intervention access site. Efficacy end points and postprocedure cardiac enzyme were similar, but there was a nonsignificant higher frequency of periprocedural myocardial infarctions in the elinogrel arms (OR, 1.59; 95% confidence interval, 0.79 to 3.48). There was an increased incidence of dyspnea (elinogrel 50/408 [12.3%] versus clopidogrel 8/208 [3.8%]) and transaminase elevation (alanine transferase/aspartate transferase >3× the upper limit of normal; elinogrel 18/408 [4.4%] versus clopidogrel 2/208 [1.0%]) in the elinogrel arms, but there were no cases of heart block, bradycardia, hypotension, or liver failure. In patients undergoing nonurgent percutaneous coronary intervention and in comparison with clopidogrel, intravenous and oral elinogrel therapy did not significantly increase thrombolysis in myocardial infarction major or minor bleeding, although bleeding requiring medical attention was more common. The significance of these findings will need

  12. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected...... to the start-up of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular stress function formulation within the 'interchain pressure' concept agrees with the experiments. In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain...

  13. Fabrication of Al2O3 coated 2D TiO2 nanoparticle photonic crystal layers by reverse nano-imprint lithography and plasma enhanced atomic layer deposition.

    Science.gov (United States)

    Kim, Ki-Kang; Ko, Ki-Young; Ahn, Jinho

    2013-10-01

    This paper reports simple process to enhance the extraction efficiency of photoluminescence (PL) from Eu-doped yttrium oxide (Y2O3:Eu3+) thin-film phosphor (TFP). Two-dimensional (2D) photonic crystal layer (PCL) was fabricated on Y2O3:Eu3+ phosphor films by reverse nano-imprint method using TiO2 nanoparticle solution as a nano-imprint resin and a 2D hole-patterned PDMS stamp. Atomic scale controlled Al2O3 deposition was performed onto this 2D nanoparticle PCL for the optimization of the photonic crystal pattern size and stabilization of TiO2 nanoparticle column structure. As a result, the light extraction efficiency of the Y2O3:Eu3+ phosphor film was improved by 2.0 times compared to the conventional Y2O3:Eu3+ phosphor film.

  14. Reversing Discrimination: A Perspective

    Science.gov (United States)

    Pati, Gopal; Reilly, Charles W.

    1977-01-01

    Examines the debate over affirmative action and reverse discrimination, and discusses how and why the present dilemma has developed. Suggests that organizations can best address the problem through an honest, in-depth analysis of their organizational structure and management practices. (JG)

  15. Elastomers with Reversible Nanoporosity

    DEFF Research Database (Denmark)

    Szewczykowski, Piotr Przemyslaw; Andersen, K.; Schulte, Lars

    2009-01-01

    nanostructure and displays liquid-filled cavities. Upon several cycles of swelling and drying the cavities open and close in a reversible fashion. When exposed to a nonsolvent, the material remains collapsed. This discriminating behavior of liquid-material interaction holds potential for the use...

  16. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  17. REVERSE SUPPLY CHAIN

    Directory of Open Access Journals (Sweden)

    Tomasz DOMAGAŁA

    2013-10-01

    Full Text Available The paper focuses on the presentation of the reverse supply chain, of which the role in the modern business grows along with the increasing number of environmental regulations and possibilities of reducing an operating cost. The paper also describes main problems in developing the profitable chain and possibilities to take an action in order to overcome them.

  18. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  19. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  20. Double outlet right ventricle

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007328.htm Double outlet right ventricle To use the sharing features on this page, please enable JavaScript. Double outlet right ventricle (DORV) is a heart disease that is ...

  1. Role of 2-hexyl, 5-propyl resorcinol production by Pseudomonas chlororaphis PCL1606 in the multitrophic interactions in the avocado rhizosphere during the biocontrol process.

    Science.gov (United States)

    Calderón, Claudia E; de Vicente, Antonio; Cazorla, Francisco M

    2014-07-01

    Different bacterial traits can contribute to the biocontrol of soilborne phytopathogenic fungus. Among others, (1) antagonism, (2) competition for nutrients and niches, (3) induction of systemic resistance of the plants and (4) predation and parasitism are the most studied. Pseudomonas chlororaphis PCL1606 is an antagonistic rhizobacterium that produces the antifungal metabolite 2-hexyl, 5-propyl resorcinol (HPR). This bacterium can biologically control the avocado white root rot caused by Rosellinia necatrix. Confocal laser scanning microscopy of the avocado rhizosphere revealed that this biocontrol bacterium and the fungal pathogen compete for the same niche and presumably also for root exudate nutrients. The use of derivative mutants in the geners related to HPR biosynthesis (dar genes) revealed that the lack of HPR production by P. chlororaphis PCL1606 negatively influences the bacterial colonisation of the avocado root surface. Microscopical analysis showed that P. chlororaphis PCL1606 closely interacts and colonises the fungal hyphae, which may represent a novel biocontrol mechanism in this pseudomonad. Additionally, the presence of HPR-producing biocontrol bacteria negatively affects the ability of the fungi to infect the avocado root. HPR production negatively affects hyphal growth, leading to alterations in the R. necatrix physiology visible under microscopy, including the curling, vacuolisation and branching of hyphae, which presumably affects the colonisation and infection abilities of the fungus. This study provides the first report of multitrophic interactions in the avocado rhizosphere, advancing our understanding of the role of HPR production in those interactions. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  2. Double Outlet Right Ventricle

    Science.gov (United States)

    ... Right Ventricle Menu Topics Topics FAQs Double Outlet Right Ventricle Double outlet right ventricle (DORV) is a rare form of congenital heart disease. Article Info En español Double outlet right ventricle (DORV) is a rare form of congenital ...

  3. Interaction between Reverse Transcriptase and Integrase Is Required for Reverse Transcription during HIV-1 Replication.

    Science.gov (United States)

    Tekeste, Shewit S; Wilkinson, Thomas A; Weiner, Ethan M; Xu, Xiaowen; Miller, Jennifer T; Le Grice, Stuart F J; Clubb, Robert T; Chow, Samson A

    2015-12-01

    Human immunodeficiency virus type 1 (HIV-1) replication requires reverse transcription of its RNA genome into a double-stranded cDNA copy, which is then integrated into the host cell chromosome. The essential steps of reverse transcription and integration are catalyzed by the viral enzymes reverse transcriptase (RT) and integrase (IN), respectively. In vitro, HIV-1 RT can bind with IN, and the C-terminal domain (CTD) of IN is necessary and sufficient for this binding. To better define the RT-IN interaction, we performed nuclear magnetic resonance (NMR) spectroscopy experiments to map a binding surface on the IN CTD in the presence of RT prebound to a duplex DNA construct that mimics the primer-binding site in the HIV-1 genome. To determine the biological significance of the RT-IN interaction during viral replication, we used the NMR chemical shift mapping information as a guide to introduce single amino acid substitutions of nine different residues on the putative RT-binding surface in the IN CTD. We found that six viral clones bearing such IN substitutions (R231E, W243E, G247E, A248E, V250E, and I251E) were noninfectious. Further analyses of the replication-defective IN mutants indicated that the block in replication took place specifically during early reverse transcription. The recombinant INs purified from these mutants, though retaining enzymatic activities, had diminished ability to bind RT in a cosedimentation assay. The results indicate that the RT-IN interaction is functionally relevant during the reverse transcription step of the HIV-1 life cycle. To establish a productive infection, human immunodeficiency virus type 1 (HIV-1) needs to reverse transcribe its RNA genome to create a double-stranded DNA copy and then integrate this viral DNA genome into the chromosome of the host cell. These two essential steps are catalyzed by the HIV-1 enzymes reverse transcriptase (RT) and integrase (IN), respectively. We have shown previously that IN physically interacts

  4. Posterior reversible encephalopathy syndrome.

    Science.gov (United States)

    Fischer, Marlene; Schmutzhard, Erich

    2017-08-01

    The posterior reversible encephalopathy syndrome (PRES) is a neurological disorder of (sub)acute onset characterized by varied neurological symptoms, which may include headache, impaired visual acuity or visual field deficits, disorders of consciousness, confusion, seizures, and focal neurological deficits. In a majority of patients the clinical presentation includes elevated arterial blood pressure up to hypertensive emergencies. Neuroimaging, in particular magnetic resonance imaging, frequently shows a distinctive parieto-occipital pattern with a symmetric distribution of changes reflecting vasogenic edema. PRES frequently develops in the context of cytotoxic medication, (pre)eclampsia, sepsis, renal disease or autoimmune disorders. The treatment is symptomatic and is determined by the underlying condition. The overall prognosis is favorable, since clinical symptoms as well as imaging lesions are reversible in most patients. However, neurological sequelae including long-term epilepsy may persist in individual cases.

  5. Reversible dysphasia and statins.

    Science.gov (United States)

    Davies, Gordon Robert Wyndham

    2012-04-01

    This paper presents a case of reversible dysphasia occurring in a patient prescribed atorvastatin in combination with indapamide. A milder dysphasia recurred with the prescription of rosuvastatin and was documented on clinical examination. This resolved following cessation of rosuvastatin. The case highlights both a need for a wider understanding of potential drug interactions through the CYP 450 system and for an increased awareness, questioning and reporting of drug side-effects.

  6. Study of the effect of ionizing radiation on composites based on PCL/PLLA and coconut fiber; Avaliacao dos efeitos da radiacao ionizante em compositos de PCL/PLLA com fibra de coco

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Yasko

    2011-07-01

    Plastic solid waste has become a serious problem recently concerning environmental impact. In this scenario, preparation of polymers and composites based on coconut husk fiber would lead to a reduction on the cost of the final product. Additionally, it will reduce the amount of agribusiness waste disposal in the environment. In Brazil, coconut production is around 1.5 billion fruits by year in a cultivated area of 2.7 million hectares, but the coconut husk fiber has not been used much for industrial applications. Moreover, biodegradable polymers have attracted the attention of the most part of population, due to the environmental issues arising from the increasing use of polymeric materials of low degradability discharged as waste residue. Besides, when considering an application in the medical field, it is necessary that the products are sterilized and, ionizing radiation is widely used to sterilize medical and surgical devices. In this work, it was studied blends and composites based on two commercial polymers: poly (e-caprolactone), PCL, and poly (lactic acid), PLLA, and coconut fiber. Those polymers are biodegradable as well as biocompatible, so it is important to know the effect of ionizing radiation in these materials. Samples were irradiated with gamma rays from {sup 60}Co source and electron beam with radiation doses ranging from 10 kGy up to 1 MGy. The non-irradiated and irradiated samples were studied using several analytical techniques and characterization assays that allowed understanding their properties in order to enable their application as precursors for medical and surgical devices. Thermal stability of non irradiated and irradiated composites up to 100 kGy radiation dose is not affected significantly by the coconut fiber incorporation to the polymeric matrix. Acetylation of fibers was not effective in order to induce any interaction between fibers and polymeric matrix, as expected. That was verified by the slight reduction of stress strength

  7. Lassa Virus Reverse Genetics.

    Science.gov (United States)

    Martínez-Sobrido, Luis; Paessler, Slobodan; de la Torre, Juan Carlos

    2017-01-01

    The Old World (OW) arenavirus Lassa (LASV ) is estimated to infect several hundred thousand people yearly in West Africa, resulting in high numbers of Lassa fever (LF), a viral hemorrhagic fever (HF) disease associated with high morbidity and mortality. To date, no licensed vaccines are available to LASV infections, and anti-LASV drug therapy is limited to an off-label use of ribavirin (Rib) that is only partially effective. The development of reverse genetics has provided investigators with a novel and powerful approach for the investigation of the molecular, cell biology, and pathogenesis of LASV. The use of cell-based LASV minigenome (MG) systems has allowed examining the cis- and trans-acting factors involved in genome replication and gene transcription and the identification of novel drugable LASV targets. Likewise, it is now feasible to rescue infectious recombinant (r)LASV entirely from cloned cDNAs containing predetermined mutations in their genomes to investigate virus-host interactions and mechanisms of pathogenesis, as well as to facilitate screens to identify antiviral drugs against LASV and the implementation of novel strategies to develop live-attenuated vaccines (LAV). In this chapter we will summarize the state-of-the-art experimental procedures for implementation of LASV reverse genetics. In addition, we will briefly discuss some significant translational research developments that have been made possible upon the development of LASV reverse genetics.

  8. Reversible multi-head finite automata characterize reversible logarithmic space

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock

    2012-01-01

    Deterministic and non-deterministic multi-head finite automata are known to characterize the deterministic and non- deterministic logarithmic space complexity classes, respectively. Recently, Morita introduced reversible multi-head finite automata (RMFAs), and posed the question of whether RMFAs...... characterize reversible logarithmic space as well. Here, we resolve the question affirmatively, by exhibiting a clean RMFA simulation of logarithmic space reversible Turing machines. Indirectly, this also proves that reversible and deterministic multi-head finite automata recognize the same languages....

  9. Double Helix Nodal Line Superconductor

    Science.gov (United States)

    Sun, Xiao-Qi; Lian, Biao; Zhang, Shou-Cheng

    2017-10-01

    Time-reversal invariant superconductors in three dimensions may contain nodal lines in the Brillouin zone, which behave as Wilson loops of 3D momentum-space Chern-Simons theory of the Berry connection. Here we study the conditions of realizing linked nodal lines (Wilson loops), which yield a topological contribution to the thermal magnetoelectric coefficient that is given by the Chern-Simons action. We find the essential conditions are the existence of torus or higher genus Fermi surfaces and spiral spin textures. We construct such a model with two torus Fermi surfaces, where a generic spin-dependent interaction leads to double-helix-like linked nodal lines as the superconductivity is developed.

  10. Double Helix Nodal Line Superconductor.

    Science.gov (United States)

    Sun, Xiao-Qi; Lian, Biao; Zhang, Shou-Cheng

    2017-10-06

    Time-reversal invariant superconductors in three dimensions may contain nodal lines in the Brillouin zone, which behave as Wilson loops of 3D momentum-space Chern-Simons theory of the Berry connection. Here we study the conditions of realizing linked nodal lines (Wilson loops), which yield a topological contribution to the thermal magnetoelectric coefficient that is given by the Chern-Simons action. We find the essential conditions are the existence of torus or higher genus Fermi surfaces and spiral spin textures. We construct such a model with two torus Fermi surfaces, where a generic spin-dependent interaction leads to double-helix-like linked nodal lines as the superconductivity is developed.

  11. The effect of controlled release of PDGF-BB from heparin-conjugated electrospun PCL/gelatin scaffolds on cellular bioactivity and infiltration

    Science.gov (United States)

    Lee, Jongman; Yoo, James J.; Atala, Anthony; Lee, Sang Jin

    2013-01-01

    Heparin-conjugated electrospun poly(ε-caprolactone) (PCL)/gelatin scaffolds were developed to provide controlled release of platelet-derived growth factor-BB (PDGF-BB) and allow prolonged bioactivity of this molecule. A mixture of PCL and gelatin was electrospun into three different morphologies. Next, heparin molecules were conjugated to the reactive surface of the scaffolds. This heparin-conjugated scaffold allowed the immobilization of PDGF-BB via electrostatic interaction. In vitro PDGF-BB release profiles indicated that passive physical adsorption of PDGF-BB to non-heparinized scaffolds resulted in an initial burst release of PDGF-BB within 5 days, which then leveled off. However, electrostatic interaction between PDGF-BB and the heparin-conjugated scaffolds gave rise to a sustained release of PDGF-BB over the course of 20 days without an initial burst. Moreover, PDGF-BB that was strongly bound to the heparin-conjugated scaffolds enhanced smooth muscle cell (SMC) proliferation. In addition, scaffolds composed of 3.0 µm diameter fibers that were immobilized with PDGF-BB accelerated SMC infiltration into the scaffold when compared to scaffolds composed of smaller diameter fibers or scaffolds that did not release PDGF-BB. We concluded that the combination of the large pore structure in the scaffolds and the heparin-mediated delivery of PDGF-BB provided the most effective cellular interactions through synergistic physical and chemical cues. PMID:22770570

  12. An in vitro toxicity evaluation of gold-, PLLA- and PCL-coated silica nanoparticles in neuronal cells for nanoparticle-assisted laser-tissue soldering.

    Science.gov (United States)

    Koch, Franziska; Möller, Anja-M; Frenz, Martin; Pieles, Uwe; Kuehni-Boghenbor, Kathrin; Mevissen, Meike

    2014-08-01

    The uptake of silica (Si) and gold (Au) nanoparticles (NPs) engineered for laser-tissue soldering in the brain was investigated using microglial cells and undifferentiated and differentiated SH-SY5Y cells. It is not known what effects NPs elicit once entering the brain. Cellular uptake, cytotoxicity, apoptosis, and the potential induction of oxidative stress by means of depletion of glutathione levels were determined after NP exposure at concentrations of 10(3) and 10(9)NPs/ml. Au-, silica poly (ε-caprolactone) (Si-PCL-) and silica poly-L-lactide (Si-PLLA)-NPs were taken up by all cells investigated. Aggregates and single NPs were found in membrane-surrounded vacuoles and the cytoplasm, but not in the nucleus. Both NP concentrations investigated did not result in cytotoxicity or apoptosis, but reduced glutathione (GSH) levels predominantly at 6 and 24h, but not after 12 h of NP exposure in the microglial cells. NP exposure-induced GSH depletion was concentration-dependent in both cell lines. Si-PCL-NPs induced the strongest effect of GSH depletion followed by Si-PLLA-NPs and Au-NPs. NP size seems to be an important characteristic for this effect. Overall, Au-NPs are most promising for laser-assisted vascular soldering in the brain. Further studies are necessary to further evaluate possible effects of these NPs in neuronal cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Predictive validity of risk assessments in juvenile offenders: Comparing the SAVRY, PCL:YV, and YLS/CMI with unstructured clinical assessments.

    Science.gov (United States)

    Hilterman, Ed L B; Nicholls, Tonia L; van Nieuwenhuizen, Chijs

    2014-06-01

    This study examined the validity and reliability of the Structured Assessment of Violence Risk in Youth (SAVRY), the Youth Level of Service/Case Management Inventory (YLS/CMI), and the Psychopathy Checklist: Youth Version (PCL:YV) in a sample of Spanish adolescents with a community sanction (N = 105). Self-reported delinquency with a follow-up period of 1 year was used as the outcome measure. The predictive validity of the three measures was compared with the unstructured judgment of the juvenile's probation officer and the self-appraisal of the juvenile. The three measures showed moderate effect sizes, ranging from area under the curve (AUC) = .75 (SAVRY) to AUC = .72 (PCL:YV), in predicting juvenile reoffending. The two unstructured judgments had no significant predictive validity whereas the SAVRY had significantly higher predictive validity compared with both unstructured judgments. Finally, SAVRY protective factor total scores and SAVRY summary risk ratings did not add incremental validity over SAVRY risk total scores. The high base rates of both violent (65.4%) and general reoffending (81.9%) underline the need for further risk assessment and management research with this population. © The Author(s) 2013.

  14. Myosin-1 inhibition by PClP affects membrane shape, cortical actin distribution and lipid droplet dynamics in early Zebrafish embryos.

    Directory of Open Access Journals (Sweden)

    Prabuddha Gupta

    Full Text Available Myosin-1 (Myo1 represents a mechanical link between the membrane and actin-cytoskeleton in animal cells. We have studied the effect of Myo1 inhibitor PClP in 1-8 cell Zebrafish embryos. Our results indicate a unique involvement of Myo1 in early development of Zebrafish embryos. Inhibition of Myo1 (by PClP and Myo2 (by Blebbistatin lead to arrest in cell division. While Myo1 isoforms appears to be important for both the formation and the maintenance of cleavage furrows, Myo2 is required only for the formation of furrows. We found that the blastodisc of the embryo, which contains a thick actin cortex (~13 μm, is loaded with cortical Myo1. Myo1 appears to be crucial for maintaining the blastodisc morphology and the actin cortex thickness. In addition to cell division and furrow formation, inhibition of Myo1 has a drastic effect on the dynamics and distribution of lipid droplets (LDs in the blastodisc near the cleavage furrow. All these results above are effects of Myo1 inhibition exclusively; Myo2 inhibition by blebbistatin does not show such phenotypes. Therefore, our results demonstrate a potential role for Myo1 in the maintenance and formation of furrow, blastodisc morphology, cell-division and LD organization within the blastodisc during early embryogenesis.

  15. Solid-liquid equilibrium measurements for the ternary system PCL + chloroform + nonsolvents (n-hexane, ethanol, methanol, isopropanol at 303.15 K - doi: 10.4025/actascitechnol.v36i1.16615

    Directory of Open Access Journals (Sweden)

    Loyse Tussolini Albini

    2014-01-01

    Full Text Available This work reports experimental data of polycaprolactone (PCL polymer solubility in chloroform as solvent and n-hexane, methanol, ethanol and isopropanol as nonsolvents, at atmospheric pressure (about 1,0 bar and temperature of 303.15 K. It was used PCL with 70000-90000 and 2000 molar mass (MM. The experiments of solubility were performed using a jacketed-cell with temperature controlled by an ultrathermostatic bath, in which a turbidity method was adopted and used. From the obtained results it should be observed that the n-hexane presented a more pronounced anti-solvent effect in the PCL solubility, where the heterogeneous region (solid phase presence was broader than when other nonsolvent. It was also observed that the binodal curves measured with the high molar mass polymer showed similar results compared to the low molar mass one.

  16. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  17. Aqueous self-assembly of poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) copolymers: disparate diblock copolymer compositions give rise to nano- and meso-scale bilayered vesicles.

    Science.gov (United States)

    Qi, Wei; Ghoroghchian, P Peter; Li, Guizhi; Hammer, Daniel A; Therien, Michael J

    2013-11-21

    Nanoparticles formed from diblock copolymers of FDA approved PEO and PCL have generated considerable interest as in vivo drug delivery vehicles. Herein, we report the synthesis of the most extensive family PEO-b-PCL copolymers that vary over the largest range of number-average molecular weights (Mn: 3.6-57k), PEO weight fractions (fPEO: 0.08-0.33), and PEO chain lengths (0.75-5.8k) reported to date. These polymers were synthesized in order to establish the full range of aqueous phase behaviours of these diblock copolymers and to specifically identify formulations that were able to generate bilayered vesicles (polymersomes). Cryogenic transmission electron microscopy (cryo-TEM) was utilized in order to visualize the morphology of these structures upon aqueous self-assembly of dry polymer films. Nanoscale polymersomes were formed from PEO-b-PCL copolymers over a wide range of PEO weight fractions (fPEO: 0.14-0.27) and PEO molecular weights (0.75-3.8k) after extrusion of aqueous suspensions. Comparative morphology diagrams, which describe the nature of self-assembled structures as a function of diblock copolymer molecular weight and PEO weight fraction, show that in contrast to micron-scale polymersomes, which form only from a limited range of PEO-b-PCL diblock copolymer compositions, a multiplicity of PEO-b-PCL diblock copolymer compositions are able to give rise to nanoscale vesicles. These data underscore that PEO-b-PCL compositions that spontaneously form micron-sized polymersomes, as well as those that have previously been reported to form polymersomes via a cosolvent fabrication system, provide only limited insights into the distribution of PEO-b-PCL diblocks that give rise to nanoscale vesicles. The broad range of polymersome-forming PEO-b-PCL compositions described herein suggest the ability to construct extensive families of nanoscale vesicles of varied bilayer thickness, providing the ability to tune the timescales of vesicle degradation and encapsulant

  18. Aqueous Self-Assembly of Poly(ethylene oxide)-block-Poly(ε-caprolactone) (PEO-b-PCL) Copolymers: Disparate Diblock Copolymer Compositions Give Rise to Nano- and Meso-Scale Bilayered Vesicles†

    Science.gov (United States)

    Qi, Wei; Ghoroghchian, P. Peter; Li, Guizhi; Hammer, Daniel A.; Therien, Michael J.

    2013-01-01

    Nanoparticles formed from diblock copolymers of FDA approved PEO and PCL have generated considerable interest as in vivo drug delivery vehicles. Herein, we report the synthesis of the most extensive family PEO-b-PCL copolymers that vary over the largest range of number-average molecular weights (Mn: 3.6 – 57K), PEO weight fractions (fPEO: 0.08 – 0.33), and PEO chain lengths (0.75–5.8K) reported to date. These polymers were synthesized in order to establish the full range of aqueous phase behaviours of these diblock copolymers and to specifically identify formulations that were able to generate bilayered vesicles (polymersomes). Cryogenic transmission electron microscopy (cryo-TEM) was utilized in order to visualize the morphology of these structures upon aqueous self-assembly of dry polymer films. Nanoscale polymersomes were formed from PEO-b-PCL copolymers over a wide range of PEO weight fractions (fPEO: 0.14 – 0.27) and PEO molecular weights (0.75 – 3.8K) after extrusion of aqueous suspensions. Comparative morphology diagrams, which describe the nature of self-assembled structures as a function of diblock copolymer molecular weight and PEO weight fraction, show that in contrast to micron-scale polymersomes, which form only from a limited range of PEO-b-PCL diblock copolymer compositions, a multiplicity of PEO-b-PCL diblock copolymer compositions are able to give rise to nanoscale vesicles. These data underscore that PEO-b-PCL compositions that spontaneously form micron-sized polymersomes, as well as those that have previously been reported to form polymersomes via a cosolvent fabrication system, provide only limited insights into the distribution of PEO-b-PCL diblocks that give rise to nanoscale vesicles. The broad range of polymersome-forming PEO-b-PCL compositions described herein suggest the ability to construct extensive families of nanoscale vesicles of varied bilayer thickness, providing the ability to tune the timescales of vesicle degradation

  19. The double identity of linguistic doubling.

    Science.gov (United States)

    Berent, Iris; Bat-El, Outi; Brentari, Diane; Dupuis, Amanda; Vaknin-Nusbaum, Vered

    2016-11-29

    Does knowledge of language consist of abstract principles, or is it fully embodied in the sensorimotor system? To address this question, we investigate the double identity of doubling (e.g., slaflaf, or generally, XX; where X stands for a phonological constituent). Across languages, doubling is known to elicit conflicting preferences at different levels of linguistic analysis (phonology vs. morphology). Here, we show that these preferences are active in the brains of individual speakers, and they are demonstrably distinct from sensorimotor pressures. We first demonstrate that doubling in novel English words elicits divergent percepts: Viewed as meaningless (phonological) forms, doubling is disliked (e.g., slaflaf Language, and their capacity to do so depends on the structure of their spoken language (English vs. Hebrew). These results demonstrate that linguistic preferences doubly dissociate from sensorimotor demands: A single stimulus can elicit diverse percepts, yet these percepts are invariant across stimulus modality--for speech and signs. These conclusions are in line with the possibility that some linguistic principles are abstract, and they apply broadly across language modality.

  20. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  1. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  2. Project Half Double

    DEFF Research Database (Denmark)

    Svejvig, Per; Ehlers, Michael; Adland, Karoline Thorp

    activities carried out within the framework of the projects. The formal part of Project Half Double was initiated in June 2015. We started out by developing, refining and testing the Half Double methodology on seven pilot projects in the first phase of the project, which will end June 2016. The current...... many of the key performance indicators associated with them can be evaluated (Grundfos and Siemens Wind Power). In addition to the current status of delivering impact faster for the seven pilot projects, it is important to highlight that Project Half Double phase 1 has planted many seeds in the pilot...... organisations concerning project methodology and beyond. The many learning points from each pilot project show that Project Half Double has left its clear footprint in the pilot organisations, and that the Half Double methodology has evolved and developed very much during Project Half Double phase 1....

  3. Double sequence core theorems

    Directory of Open Access Journals (Sweden)

    Richard F. Patterson

    1999-01-01

    Full Text Available In 1900, Pringsheim gave a definition of the convergence of double sequences. In this paper, that notion is extended by presenting definitions for the limit inferior and limit superior of double sequences. Also the core of a double sequence is defined. By using these definitions and the notion of regularity for 4-dimensional matrices, extensions, and variations of the Knopp Core theorem are proved.

  4. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  5. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages...... flowcharts are both expressive and robust: reversible flowcharts can simulate irreversible ones, by adapting reversibilization techniques to the flowchart model. Thus, reversible flowcharts are r-Turing-complete, meaning that they can compute exactly all injective computable functions. Furthermore......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...

  6. Improved tumor tissue penetration and tumor cell uptake achieved by delayed charge reversal nanoparticles.

    Science.gov (United States)

    Gou, Jingxin; Liang, Yuheng; Miao, Linlin; Guo, Wei; Chao, Yanhui; He, Haibing; Zhang, Yu; Yang, Jingyu; Wu, Chunfu; Yin, Tian; Wang, Yanjiao; Tang, Xing

    2017-10-15

    The high affinity of positively charged nanoparticles to biological interfaces makes them easily taken up by tumor cells but limits their tumor permeation due to non-specific electrostatic interactions. In this study, polyion complex coated nanoparticles with different charge reversal profiles were developed to study the influence of charge reversal profile on tumor penetration. The system was constructed by polyion complex coating using micelles composed of poly (lysine)-b-polycaprolactone (PLys-b-PCL) as the cationic core and poly (glutamic acid)-g- methoxyl poly (ethylene glycol) (PGlu-g-mPEG) as the anionic coating material. Manipulation of charge reversal profile was achieved by controlling the polymer chain entanglement and electrostatic interaction in the polyion complex layer through glutaraldehyde-induced shell-crosslinking. The delayed charge reversal nanoparticles (CTCL30) could maintain negatively charged in pH 6.5 PBS for at least 2h and exhibit pH-responsive cytotoxicity and cellular uptake in an extended time scale. Compared with a faster charge reversal counterpart (CTCL70) with similar pharmacokinetic profile, CTCL30 showed deeper penetration, higher in vivo tumor cell uptake and stronger antitumor activity in vivo (tumor inhibition rate: 72.3% vs 60.2%, compared with CTCL70). These results indicate that the delayed charge reversal strategy could improve therapeutic effect via facilitating tumor penetration. Here, the high tumor penetration capability of PEG-coated nanoparticles and the high cellular uptake of cationic nanoparticles were combined by a delayed charge reversal drug delivery system. This drug delivery system was composed of a drug-loading cationic inner core and a polyion complex coating. Manipulation of charge reversal profile was realized by varying the crosslinking degree of the shell of the cationic inner core, through which changed the strength of the polyion complex layer. Nanoparticles with delayed charge reversal profile

  7. Synthesis, structure and reductive dechlorination of the C-centred phosphorus(III) beta-diketiminate PCl(Ph)L [L = C[C(Me)NC6H3Pri2(-2),6][C(Me)NHC6H3Pri2(-2),6

    Science.gov (United States)

    Hitchcock, Peter B; Lappert, Michael F; Nycz, Jacek E

    2003-05-21

    Treatment of the beta-diketimine HL with successively LiBun and PCl2Ph gave the first C-centered monodentate beta-diketiminate PCl(Ph)L 1; with C8K 1 underwent reductive dechlorination yielding 2, a novel N-PIII-PIII-C=C heterocycle.

  8. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  9. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    2012-10-06

    Oct 6, 2012 ... The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. Keywords. Double beta ...

  10. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  11. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  12. Sex Reversal in Amphibians.

    Science.gov (United States)

    Flament, Stéphane

    2016-01-01

    Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing this process are reviewed. In the second part, the state of the art about sex reversal, which can be induced by steroid hormones in general and by temperature in some species, is presented. Also information about pollutants found in the environment that could interfere with the development of the amphibian reproductive apparatus or with their reproductive physiology is given. Such compounds could play a part in the amphibian decline, since in the wild, many amphibians are endangered species. © 2016 S. Karger AG, Basel.

  13. A reversible processor architecture and its reversible logic design

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    an architecture with an ISA that is expressive enough to serve as the target for a compiler from a high-level structured reversible programming language. All-in-all, this paper demonstrates that the design of a complete reversible computing architecture is possible and can serve as the core of a programmable......We describe the design of a purely reversible computing architecture, Bob, and its instruction set, BobISA. The special features of the design include a simple, yet expressive, locally-invertible instruction set, and fully reversible control logic and address calculation. We have designed...

  14. Nanocomposites Based on PCL and Halloysite Nanotubes Filled with Lysozyme: Effect of Draw Ratio on the Physical Properties and Release Analysis

    Directory of Open Access Journals (Sweden)

    Valeria Bugatti

    2017-08-01

    Full Text Available Halloysite nanotubes (HNTs were loaded with lsozyme, as antimicrobial molecule, at a HNTs/lysozyme ratio of 1:1. Such a nano-hybrid was incorporated into a poly (ε-caprolactone (PCL matrix at 10 wt % and films were obtained. The nano-composites were submitted to a cold drawn process at three different draw ratios, λ = 3, 4, and 5, where λ is l(final length/l0(initial length. Morphology, physical, and barrier properties of the starting nanocomposite and drawn samples were studied, and correlated to the release of the lysozyme molecule. It was demonstrated that with a simple mechanical treatment it is possible to obtain controlled release systems for specific active packaging requirements.

  15. Dyspnea and reversibility of antiplatelet agents: ticagrelor, elinogrel, cangrelor, and beyond.

    Science.gov (United States)

    Serebruany, Victor L; Sibbing, Dirk; DiNicolantonio, James J

    2014-01-01

    Oral reversible platelet P2Y12 receptor inhibitors (ticagrelor and elinogrel) cause double-digit rates of dyspnea, while irreversible oral antiplatelet drugs (aspirin, ticlopidoine, clopidogrel, and prasugrel) or intravenous glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, or tirofiban) do not increase the incidence of dyspnea in randomized trials. Dyspnea after oral reversible antiplatelet agents remains unexplained. A transfusion-related acute lung injury (TRALI) hypothesis has been proposed. The dyspnea risks after cangrelor, an intravenous reversible antiplatelet agent, are not well defined but may offer a universal mechanism linking TRALI, dyspnea, and reversible platelet inhibition. We analyzed safety data from recent head-to-head randomized trials with reversible antiplatelet agents (ticagrelor, elinogrel, and cangrelor) compared to irreversible (clopidogrel/placebo) comparators. All three reversible antiplatelet agents cause excess dyspnea. In contrast to the high double-digit rates after oral ticagrelor or elinogrel, the dyspnea risks after intravenous cangrelor were smaller (<2%) but still consistently and significantly higher than in the corresponding control arms. The clinical utility of reversible antiplatelet strategies has been challenged. Despite a potential advantage of fewer bleeding events during heart surgery, reversible antiplatelet agents carry the risk of potential autoimmune reactions manifesting as dyspnea. Repeated binding and unbinding cycles, impaired platelet turnover, and lung sequestration or apoptosis of overloaded destructive platelets are among the potential mechanism(s) responsible for dyspnea after reversible antiplatelet agents.

  16. A biodegradable porous composite scaffold of PCL/BCP containing Ang-(1-7 for bone tissue engineering Um suporte compósito poroso biodegradável de PCL/BCP contendo Ang-(1-7 para engenharia de tecido ósseo

    Directory of Open Access Journals (Sweden)

    F. A. Macedo

    2012-12-01

    Full Text Available Highly porous three-dimensional biodegradable scaffolds was obtained from beta-tricalcium phosphate-hydroxyapatite bioceramic (BCP, PCL, and Angiotensin-(1-7. We used the solvent casting and particulate leaching methods (SC/PL. The processed scaffolds were characterized by X-ray microtomography (µ-CT. Biocompatibility tests in vitro were performed during three and seven days using MTT and Alkaline Phosphatase Activity (APA assays. Both the MTT activity and APA were evaluated using a one-way ANOVA test. The µ-CT results showed that the increase of the PCL:BCP weight ratio leads to structures with lower pore sizes. The pore interconnectivity of the processed scaffolds was evaluated in terms of the fragmentation index (FI. We observed that the obtained composites present poorly connected structures, with close values of FI. However, as the polymer phase is almost transparent to the X-rays, it was not taken into consideration in the µ-CT tests. The MTT activity assay revealed that scaffolds obtained with and without Angiotensin-(1-7 present mild and moderate cytotoxic effects, respectively. The APA assay showed that the rat osteoblasts, when in contact for three days with the PCL composites, presented an APA similar to that observed for the control cells. Nevertheless, for an incubation time of seven days we observed a remarkable decrease in the alkaline phosphatase activity. In conclusion, using the solvent casting and salt leaching method we obtained 3D porous that are composites of PCL, BC and Ang-(1-7, which have suitable shapes for the bone defects, a high porosity and interconnect pores. Furthermore, the viability in vitro showed that the scaffolds have potential for drug delivery system and could be used in future in vivo tests.A estrutura de um biomaterial para regeneração óssea é fator chave para seu sucesso clínico. Não existe um único biomaterial usado para reparo e regeneração óssea capaz de preencher todos os requisitos

  17. Aqueous self-assembly of poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) copolymers: disparate diblock copolymer compositions give rise to nano- and meso-scale bilayered vesicles

    Science.gov (United States)

    Qi, Wei; Ghoroghchian, P. Peter; Li, Guizhi; Hammer, Daniel A.; Therien, Michael J.

    2013-10-01

    Nanoparticles formed from diblock copolymers of FDA approved PEO and PCL have generated considerable interest as in vivo drug delivery vehicles. Herein, we report the synthesis of the most extensive family PEO-b-PCL copolymers that vary over the largest range of number-average molecular weights (Mn: 3.6-57k), PEO weight fractions (fPEO: 0.08-0.33), and PEO chain lengths (0.75-5.8k) reported to date. These polymers were synthesized in order to establish the full range of aqueous phase behaviours of these diblock copolymers and to specifically identify formulations that were able to generate bilayered vesicles (polymersomes). Cryogenic transmission electron microscopy (cryo-TEM) was utilized in order to visualize the morphology of these structures upon aqueous self-assembly of dry polymer films. Nanoscale polymersomes were formed from PEO-b-PCL copolymers over a wide range of PEO weight fractions (fPEO: 0.14-0.27) and PEO molecular weights (0.75-3.8k) after extrusion of aqueous suspensions. Comparative morphology diagrams, which describe the nature of self-assembled structures as a function of diblock copolymer molecular weight and PEO weight fraction, show that in contrast to micron-scale polymersomes, which form only from a limited range of PEO-b-PCL diblock copolymer compositions, a multiplicity of PEO-b-PCL diblock copolymer compositions are able to give rise to nanoscale vesicles. These data underscore that PEO-b-PCL compositions that spontaneously form micron-sized polymersomes, as well as those that have previously been reported to form polymersomes via a cosolvent fabrication system, provide only limited insights into the distribution of PEO-b-PCL diblocks that give rise to nanoscale vesicles. The broad range of polymersome-forming PEO-b-PCL compositions described herein suggest the ability to construct extensive families of nanoscale vesicles of varied bilayer thickness, providing the ability to tune the timescales of vesicle degradation and encapsulant

  18. Genome Analysis of Pseudomonas fluorescens PCL1751: A Rhizobacterium that Controls Root Diseases and Alleviates Salt Stress for Its Plant Host.

    Directory of Open Access Journals (Sweden)

    Shu-Ting Cho

    Full Text Available Pseudomonas fluorescens PCL1751 is a rod-shaped Gram-negative bacterium isolated from the rhizosphere of a greenhouse-grown tomato plant in Uzbekistan. It controls several plant root diseases caused by Fusarium fungi through the mechanism of competition for nutrients and niches (CNN. This mechanism does not rely on the production of antibiotics, so it avoids the concerns of resistance development and is environmentally safe. Additionally, this bacterium promotes plant growth by alleviating salt stress for its plant host. To investigate the genetic mechanisms that may explain these observations, we determined the complete genome sequence of this bacterium, examined its gene content, and performed comparative genomics analysis with other Pseudomonas strains. The genome of P. fluorescens PCL1751 consisted of one circular chromosome that is 6,143,950 base-pairs (bp in size; no plasmid was found. The annotation included 19 rRNA, 70 tRNA, and 5,534 protein-coding genes. The gene content analysis identified a large number of genes involved in chemotaxis and motility, colonization of the rhizosphere, siderophore biosynthesis, and osmoprotectant production. In contrast, the pathways involved in the biosynthesis of phytohormones or antibiotics were not found. Comparison with other Pseudomonas genomes revealed extensive variations in their genome size and gene content. The presence and absence of secretion system genes were highly variable. As expected, the synteny conservation among strains decreased as a function of phylogenetic divergence. The integration of prophages appeared to be an important driver for genome rearrangements. The whole-genome gene content analysis of this plant growth-promoting rhizobacterium (PGPR provided some genetic explanations to its phenotypic characteristics. The extensive and versatile substrate utilization pathways, together with the presence of many genes involved in competitive root colonization, provided further support

  19. Modifications induced by swift heavy ions on poly(hydroxybutyrate-hydroxyvalerate) (PHB/HV) and poly({epsilon}-caprolactone) (PCL). Part 2. Radicals characterization

    Energy Technology Data Exchange (ETDEWEB)

    Rouxhet, L.; Mestdagh, M.; Legras, R. E-mail: legras@poly.ucl.ac.be

    2000-12-01

    Modifications induced by different energetic heavy ions ({sub 40}Ar{sup 9+}, {sub 80}Kr{sup 15+}, {sub 129}Xe{sup 24+}, {sub 208}Pb{sup 53+} and {sub 208}Pb{sup 56+}) on poly({epsilon}-caprolactone) (PCL) and poly(hydroxybutyrate-hydroxyvalerate) (PHB/HV) have been investigated by electron spin resonance (ESR). Indeed, film irradiation by heavy ions leads to, among other phenomena, the formation of radicals in the ion tracks. Thanks to ESR, it is possible to detect these radicals and to identify them or at least to characterize them by following the evolution of the radical signal as a function of parameters, like temperature, or the kinetic of disappearance of the radical species at ambient temperature in vacuum or ambient atmosphere. This study confirmed the generation of radicals by the irradiation of PHB/HV samples with energetic heavy ions reported in the literature. The study on PCL was not pursued after a few preliminary studies, revealing the presence of an ESR signal in the non-irradiated sample. Electronic stopping power has a major influence on radical decrease at ambient temperature. The ion used for the irradiation did not modify very much the radical signal and the evolution of the radicalar signal intensity with temperature. Different reasoning and experiments revealed that the glass transition temperature is a key temperature above which irreversible recombinations of the most stable radicals take place. A simulation study indicated that the most stable radical produced was probably a tertiary radical formed by the stabilization of the secondary radical resulting from the abstraction of a highly mobile hydrogen adjacent to the carbonyl.

  20. Defining the Polar Field Reversal

    Science.gov (United States)

    Upton, Lisa; Hathaway, David H.

    2013-01-01

    The polar fields on the Sun are directly related to solar cycle variability. Recently there has been interest in studying an important characteristic of the polar fields: the timing of the polar field reversals. However this characteristic has been poorly defined, mostly due to the limitations of early observations. In the past, the reversals have been calculated by averaging the flux above some latitude (i.e. 55deg or 75deg). Alternatively, the reversal could be defined by the time in which the previous polarity is completely canceled and replaced by the new polarity at 90de, precisely at the pole. We will use a surface flux transport model to illustrate the differences in the timing of the polar field reversal based on each of these definitions and propose standardization in the definition of the polar field reversal. The ability to predict the timing of the polar field reversal using a surface flux transport model will also be discussed.

  1. Reversing Neurodevelopmental Disorders in Adults

    National Research Council Canada - National Science Library

    Ehninger, Dan; Li, Weidong; Fox, Kevin; Stryker, Michael P; Silva, Alcino J

    2008-01-01

    .... Surprisingly, a number of recent animal model studies of neurodevelopmental disorders demonstrate that reversing the underlying molecular deficits can result in substantial improvements in function...

  2. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse gear...

  3. Congenital maxillary double lip

    Directory of Open Access Journals (Sweden)

    Dinesh Singh Chauhan

    2012-01-01

    Full Text Available Double lip, also referred to as "macrocheilia," is a rare anomaly which affects the upper lip more commonly than the lower lip. It consists of a fold of excess or redundant hypertrophic tissue on the mucosal side of the lip. The congenital double lip is believed to be present at birth and becomes more prominent after eruption of teeth. It affects esthetics and also interferes with speech and mastication. Simple surgical excision produces good functional and cosmetic results. We report a case of a non-syndromic congenital maxillary double lip in a 21-year-old male patient.

  4. [Posterior reversible encephalopathy syndrome].

    Science.gov (United States)

    Fischer, M; Schmutzhard, E

    2016-06-01

    Posterior reversible encephalopathy syndrome refers to a neurological disorder characterized by headache, disorders of consciousness, visual disturbances, epileptic seizures, and subcortical vasogenic edema. About two thirds of patients develop neurological symptoms, which are associated with blood pressure fluctuations. One hypothesis is that hypertensive episodes cause autoregulatory failure, and values above the upper limit of cerebral autoregulation result in a breakthrough followed by hyperperfusion and blood-brain barrier dysfunction. In another hypothesis, endothelial dysfunction triggered by numerous factors including preeclampsia, immunosuppressive agents, chemotherapeutics, sepsis, or autoimmune disorders is thought to be the key pathomechanism. Endo- or exogenic toxic agents including pharmacological substances, cytokines, or bacterial toxins are supposed to trigger endothelial activation and dysfunction resulting in the release of vasoconstrictors, pro-inflammatory mediators, and vascular leakage. Diagnosis is usually based on clinical and neuroimaging findings that frequently show a bilateral, symmetric, and parietooccipital pattern. However, the diagnosis can often only be confirmed during the course of disease after excluding important differential diagnoses. Currently, there is no specific treatment available. Lowering of arterial blood pressure and eliminating the underlying cause usually leads to an improvement of clinical and neuroradiological findings. Admission to a critical care unit is required in about 40 % of patients due to complicating conditions including status epilepticus, cerebral vasoconstriction, ischemia, or intracerebral hemorrhage. Prognosis is favorable; in the majority of patients neurological deficits and imaging findings resolve completely.

  5. Mechanics of reversible unzipping

    Science.gov (United States)

    Maddalena, F.; Percivale, D.; Puglisi, G.; Truskinovsky, L.

    2009-07-01

    We study the mechanics of a reversible decohesion (unzipping) of an elastic layer subjected to quasi-static end-point loading. At the micro level the system is simulated by an elastic chain of particles interacting with a rigid foundation through breakable springs. Such system can be viewed as prototypical for the description of a wide range of phenomena from peeling of polymeric tapes, to rolling of cells, working of Gecko’s fibrillar structures and denaturation of DNA. We construct a rigorous continuum limit of the discrete model which captures both stable and metastable configurations and present a detailed parametric study of the interplay between elastic and cohesive interactions. We show that the model reproduces the experimentally observed abrupt transition from an incremental evolution of the adhesion front to a sudden complete decohesion of a macroscopic segment of the adhesion layer. As the microscopic parameters vary the macroscopic response changes from quasi-ductile to quasi-brittle, with corresponding decrease in the size of the adhesion hysteresis. At the micro-scale this corresponds to a transition from a ‘localized’ to a ‘diffuse’ structure of the decohesion front (domain wall). We obtain an explicit expression for the critical debonding threshold in the limit when the internal length scales are much smaller than the size of the system. The achieved parametric control of the microscopic mechanism can be used in the design of new biological inspired adhesion devices and machines.

  6. Time Reversal Violation

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, H; /SLAC

    2009-01-27

    This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focused on the latter, namely the violation of T-reversal invariance in particle physics theories. In sum tests of microscopic T-invariance, or observations of its violation, are limited by the fact that, while we can measure many processes, only in very few cases can we construct a matched pair of process and inverse process and observe it with sufficient sensitivity to make a test. In both the cases discussed here we can achieve an observable T violation making use of flavor tagging, and in the second case also using the quantum properties of an antisymmetric coherent state of two B mesons to construct a CP-tag. Both these tagging properties depend only on very general properties of the flavor and/or CP quantum numbers and so provide model independent tests for T-invariance violations. The microscopic laws of physics are very close to T-symmetric. There are small effects that give CP- and T-violating processes in three-generation-probing weak decays. Where a T-violating observable can be constructed we see the relationships between T-violation and CP-violation expected in a CPT conserving theory. These microscopic effects are unrelated to the 'arrow of time' that is defined by increasing entropy, or in the time direction defined by the expansion of our Universe.

  7. Hybrid supercapacitors for reversible control of magnetism.

    Science.gov (United States)

    Molinari, Alan; Leufke, Philipp M; Reitz, Christian; Dasgupta, Subho; Witte, Ralf; Kruk, Robert; Hahn, Horst

    2017-05-10

    Electric field tuning of magnetism is one of the most intensely pursued research topics of recent times aiming at the development of new-generation low-power spintronics and microelectronics. However, a reversible magnetoelectric effect with an on/off ratio suitable for easy and precise device operation is yet to be achieved. Here we propose a novel route to robustly tune magnetism via the charging/discharging processes of hybrid supercapacitors, which involve electrostatic (electric-double-layer capacitance) and electrochemical (pseudocapacitance) doping. We use both charging mechanisms-occurring at the La 0.74 Sr 0.26 MnO 3 /ionic liquid interface to control the balance between ferromagnetic and non-ferromagnetic phases of La 1-x Sr x MnO 3 to an unprecedented extent. A magnetic modulation of up to ≈33% is reached above room temperature when applying an external potential of only about 2.0 V. Our case study intends to draw attention to new, reversible physico-chemical phenomena in the rather unexplored area of magnetoelectric supercapacitors.

  8. REVERSE LOGISTICS IN GLOBALIZATION ASPECTS

    OpenAIRE

    Janusz Grabara; Iwona Grabara

    2008-01-01

    This paper presents issues connected with adaptation of modern solutions of reverse logisticsmanagement in enterprise to the concept of sustainable development promoted by the European Union.Nowadays more and more businesses are looking to grow their reverse logistics capabilities in global market.

  9. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.
    In Chapter 1 the present knowledge about reversed micelles and

  10. Enzyme recovery using reversed micelles

    NARCIS (Netherlands)

    Dekker, M.

    1990-01-01

    The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.

    Reversed micelles are aggregates of surfactant

  11. MODELS OF PROJECT REVERSE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Віктор Володимирович ІВАНОВ

    2017-03-01

    Full Text Available Reverse engineering decided important scientific and technical problems of increasing the cost of the existing technical product by transforming it into a product with other features or design. Search ideas of the new application of existing products on the base of heuristic analysis were created. The concept of reverse engineering and its division into three types: conceptual, aggregate and complete was expanded. The use of heuristic methods for reverse engineering concept was showed. The modification model of Reverse engineering based on the model of РМВОК was developed. Our model includes two new phases: identification and transformation. At the identification phase, technical control is made. At the transformation phase, search heuristic idea of the new applied existing technical product was made. The model of execution phase that included heuristic methods, metrological equipment, and CAD/CAM/CAE program complex was created. The model that connected economic indicators of reverse engineering project was developed.

  12. Reversible gates and circuits descriptions

    Science.gov (United States)

    Gracki, Krzystof

    2017-08-01

    This paper presents basic methods of reversible circuit description. To design reversible circuit a set of gates has to be chosen. Most popular libraries are composed of three types of gates so called CNT gates (Control, NOT and Toffoli). The gate indexing method presented in this paper is based on the CNT gates set. It introduces a uniform indexing of the gates used during synthesis process of reversible circuits. The paper is organized as follows. Section 1 recalls basic concepts of reversible logic. In Section 2 and 3 a graphical representation of the reversible gates and circuits is described. Section 4 describes proposed uniform NCT gates indexing. The presented gate indexing method provides gate numbering scheme independent of lines number of the designed circuit. The solution for a circuit consisting of smaller number of lines is a subset of solution for a larger circuit.

  13. Reversion of pH-induced physiological drug resistance: a novel function of copolymeric nanoparticles.

    Directory of Open Access Journals (Sweden)

    Rutian Li

    Full Text Available AIMS: The extracellular pH of cancer cells is lower than the intracellular pH. Weakly basic anticancer drugs will be protonated extracellularly and display a decreased intracellular concentration. In this study, we show that copolymeric nanoparticles (NPs are able to overcome this "pH-induced physiological drug resistance" (PIPDR by delivering drugs to the cancer cells via endocytosis rather than passive diffussion. MATERIALS AND METHODS: As a model nanoparticle, Tetradrine (Tet, Pka 7.80 was incorporated into mPEG-PCL. The effectiveness of free Tet and Tet-NPs were compared at different extracellular pHs (pH values 6.8 and 7.4, respectively by MTT assay, morphological observation and apoptotic analysis in vitro and on a murine model by tumor volume measurement, PET-CT scanning and side effect evaluation in vivo. RESULTS: The cytotoxicity of free Tet decreased prominently (P<0.05 when the extracellular pH decreased from 7.4 to 6.8. Meanwhile, the cytotoxicity of Tet-NPs was not significantly influenced by reduced pH. In vivo experiment also revealed that Tet-NPs reversed PIPDR more effectively than other existing methods and with much less side effects. CONCLUSION: The reversion of PIPDR is a new discovered mechanism of copolymeric NPs. This study emphasized the importance of cancer microenvironmental factors in anticancer drug resistance and revealed the superiority of nanoscale drug carrier from a different aspect.

  14. Formation of Double Neutron Stars, Millisecond Pulsars and Double ...

    Indian Academy of Sciences (India)

    Edward P. J. Heuvel

    2017-09-12

    Sep 12, 2017 ... the double neutron stars and of double black holes is given. 2. Double neutron stars and millisecond pulsars. 2.1 Double neutron stars. In the period 1978 to 1980, Srinivasan and van den. Heuvel profoundly discussed the possible ways in which the Hulse–Taylor binary pulsar could have been formed.

  15. Reversible simulation of irreversible computation

    Science.gov (United States)

    Li, Ming; Tromp, John; Vitányi, Paul

    1998-09-01

    Computer computations are generally irreversible while the laws of physics are reversible. This mismatch is penalized by among other things generating excess thermic entropy in the computation. Computing performance has improved to the extent that efficiency degrades unless all algorithms are executed reversibly, for example by a universal reversible simulation of irreversible computations. All known reversible simulations are either space hungry or time hungry. The leanest method was proposed by Bennett and can be analyzed using a simple ‘reversible’ pebble game. The reachable reversible simulation instantaneous descriptions (pebble configurations) of such pebble games are characterized completely. As a corollary we obtain the reversible simulation by Bennett and, moreover, show that it is a space-optimal pebble game. We also introduce irreversible steps and give a theorem on the tradeoff between the number of allowed irreversible steps and the memory gain in the pebble game. In this resource-bounded setting the limited erasing needs to be performed at precise instants during the simulation. The reversible simulation can be modified so that it is applicable also when the simulated computation time is unknown.

  16. Equivalência semântica da versão em português da Post-Traumatic Stress Disorder Checklist - Civilian Version (PCL-C para rastreamento do transtorno de estresse pós-traumático Equivalencia semántica de la versión en portugués de la Post-Traumatic Stress Disorder Checklist - Civilian Version (PCL-C para el rastreo del trastorno de estrés pos-traumático Semantic equivalence of the Portuguese version of the Post-Traumatic Stress Disorder Checklist - Civilian Version (PCL-C for the screening of post-traumatic stress disorder

    Directory of Open Access Journals (Sweden)

    William Berger

    2004-08-01

    Full Text Available INTRODUÇÃO: O transtorno do estresse pós-traumático (TEPT é bastante prevalente, atingindo de 2 a 5% da população em alguns países. Seus portadores apresentam pior qualidade de vida, maior número de detenções e problemas legais, e utilizam os serviços de saúde com maior freqüência quando comparados a indivíduos não acometidos. Apesar do crescimento da violência urbana no Brasil, ainda não dispomos de nenhum instrumento adaptado para nossa língua que seja capaz de rastrear o TEPT. Este artigo pretende traduzir, adaptar e avaliar a aplicabilidade da versão em português da Post-Traumatic Stress Disorder Checklist - Civilian Version (PCL-C, uma escala auto-aplicável amplamente utilizada em todo o mundo para rastreamento do transtorno do estresse pós-traumático. MÉTODOS: A comprovação da equivalência semântica da versão em português da PCL-C foi feita através de quatro etapas: tradução; retradução; apreciação formal de equivalência e adaptação; e interlocução com a população-alvo. RESULTADOS: Foi criada uma versão em português da PCL-C que manteve o significado semântico da versão original e mostrou-se de fácil compreensão e aplicabilidade. DISCUSSÃO: A PCL-C foi escolhida para este estudo por ser um instrumento amplamente utilizado em países de língua inglesa e por possuir outras utilidades além do rastreamento do TEPT. A interlocução com a população-alvo, feita com um número relativamente pequeno de indivíduos (n = 21, mostrou que alguns participantes entenderam o termo "estresse" como uma rotina de vida cansativa. CONCLUSÃO: Uma vez obtida a equivalência semântica da versão em português da PCL-C, estudos posteriores deverão determinar suas características psicométricas para a população brasileira.INTRODUCCÍON: El trastorno de estrés postraumático (TEPT es bastante común, afectando del 2 al 5% de la población en algunos países. Quienes lo padecen presentan una inferior

  17. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  18. A Framework for Reverse Logistics

    OpenAIRE

    Brito, Marisa; Dekker, Rommert

    2003-01-01

    textabstractReverse Logistics has been stretching out worldwide, involving all the layers of supply chains in various industry sectors. While some actors in the chain have been forced to take products back, others have pro-actively done so, attracted by the value in used products One way or the other, Reverse Logistics has become a key competence in modern supply chains. In this paper, we present a content analysis of reverse logistics issues. To do so, we propose a content framework focusing...

  19. Short-Term Stock Price Reversals May Be Reversed

    Directory of Open Access Journals (Sweden)

    Andrey Kudryavtsev

    2012-12-01

    Full Text Available In present study, I explore intraday behavior of stock prices. In particular, I try to shed light onthe dynamics of stock price reversals and namely, on the short-term character the latter maypossess. For each of the stocks currently making up the Dow Jones Industrial Index, I calculateintraday upside and downside volatility measures, following Becker et al. (2008 and Klossner etal. (2012, as a proxy for reversed overreactions to good and bad news, respectively. I documentthat for all the stocks in the sample, mean daily returns following the days when a stock’supside volatility measure was higher or equal to its downside volatility measure are higher thanfollowing the days when the opposite relationship held, indicating that stock prices display ashort-run ‘reversals of reversals’ behavior following corrected, or reversed, overreactions tonews. Furthermore, I construct seven different portfolios built upon the idea of daily adjustinga long position in the stocks that according to ‘reversals of reversals’ behavior are expectedto yield high daily returns, and a short position in the stocks, whose daily returns are expectedto be low. All the portfolios yield significantly positive returns, providing an evidence for thepractical applicability of the ‘reversals of reversals’ pattern in stock prices.

  20. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    a positive correlation with the extent of reverse knowledge transfers to the parent MNE. Relying on the headquarters-subsidiary view of the MNE, we argue that, beyond a point, increasing subsidiary innovativeness will be associated with lower reverse knowledge transfers. Further, we argue...... that this relationship is sensitive to the subsidiary entry mode. Using data from a sample of 293 Italian subsidiaries, we find strong support for our hypotheses. In particular, our results confirm that the effect of subsidiary innovativeness on reverse knowledge transfers displays an inverted-U shape......, and that the curvilinearity is greater for greenfield entries relative to acquisition entries. The U-shaped relationship between subsidiary innovativeness and reverse knowledge transfers, as well as the sensitivity of this result to entry mode are important new findings in the literature on the role of subsidiaries...

  1. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    for the reverse supply chain. Design/methodology/approach – In order to identify the relevance of the Fisher model, the model needs to be recast in terms of PRV, which, in this context, is considered the independent variable in the reverse logistics arena. Products defined as innovative in Fisher's taxonomy......Purpose – The purpose of this paper is to explore the impact of the product residual value (PRV) and the loss of value over time of returned products in the reverse supply chain configuration. It also examines whether or not the distinction of Fisher's functional and innovative products holds...... correspond to disposed products with high residual value, whereas functional products correspond to disposed products with low residual value. Furthermore, the PRV and the speed at which returned products lose their value are considered in order to determine the configuration of the reverse supply chain...

  2. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    National Research Council Canada - National Science Library

    Ioana Olariu

    2014-01-01

    ... of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle...

  3. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    Reverse innovation commonly refers to an innovation initially launched in a developing country and later introduced to an advanced country. Adopting a linear innovation model with the four sequential phases of concept ideation, product development, primary target market introduction, and subsequent...... secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions...

  4. Towards a reversible functional language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    We identify concepts of reversibility for a functional language by means of a set of semantic rules with specific properties. These properties include injectivity along with local backward determinism, an important operational property for an efficient reversible language. We define a concise...... reversible first-order functional language in which access to the backward semantics is provided to the programmer by inverse function calls. Reversibility guarantees that in this language a backward run (inverse interpretation) is as fast as the corresponding forward run itself. By adopting a symmetric...... first-match policy for case expressions, we can write overlapping patterns in case branches, as is customary in ordinary functional languages, and also in leaf expressions, unlike existing inverse interpreter methods, which enables concise programs. In patterns, the use of a duplication...

  5. Porous membrane with reverse gradients of PDGF-BB and BMP-2 for tendon-to-bone repair: in vitro evaluation on adipose-derived stem cell differentiation.

    Science.gov (United States)

    Min, Hyun Ki; Oh, Se Heang; Lee, Jong Min; Im, Gun Il; Lee, Jin Ho

    2014-03-01

    Polycaprolactone (PCL)/Pluronic F127 membrane with reverse gradients of dual platelet-derived growth factor-β (PDGF-BB) and bone morphogenetic protein 2 (BMP-2) concentrations was fabricated using a diffusion method to investigate the effect of reverse gradients of dual growth factor concentrations on adipose-derived stem cell (ASC) differentiations, such as tenogenesis and osteogenesis. The PDGF-BB and BMP-2 were continuously released from the membrane for up to 35 days, with reversely increasing/decreasing growth factors along the membrane length. Human ASCs were seeded on the membrane with reverse PDGF-BB and BMP-2 gradients. The cells were confluent after 1 week of culture, regardless of growth factor types or concentrations on the membrane. Gene expression (real-time polymerase chain reaction), Western blot and immunohistological analyses after 1 and 2 weeks of ASC culture showed that the membrane sections with higher PDGF-BB and lower BMP-2 concentrations provided a better environment for ASC tenogenesis, while the membrane sections with higher BMP-2 and lower PDGF-BB concentrations were better for promoting osteogenesis. The results suggest that the membrane with reverse gradients of PDGF-BB and BMP-2 may be promising for tendon-to-bone repair, as most essential biological processes are mediated by gradients of biological molecules in the body. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients.......A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients....

  7. Deterministic chaos in geomagnetic reversals

    Science.gov (United States)

    Sidorovskaia, N.; Richter, C.; Rypina, I.

    2013-12-01

    In a recent publication Gissinger (Eur. Phys. J. B 85,137, 2012) proposed a new deterministic chaos model for the generation of the Earth's magnetic field and an explanation of the observed statistics of geomagnetic pole reversal occurrences. The new model is described by a system of three coupled non-linear differential equations limited to quadratic terms. If such a low degree of freedom system is adequate for the description of Earth's geomagnetic dynamo, it has to reflect in statistics and non-linear dynamic characteristics of the temporal interval between geomagnetic reversals. We present the results of the extended statistical analysis of the 2012 compilation of magnetic reversal data spanning the last 170 m.yr. We calculate the Grassberger-Procaccia correlation dimension in the context of a single-variable dataset of waiting times between measured geomagnetic reversals in paleomagnetic records to predict the complexity of the underlying geomagnetic dynamo system. First, we inspect if the time series of geomagnetic reversals has the same or a different correlation dimension than a random time series with the same number of points. This allows us to determine whether geomagnetic reversals are indistinguishable from a stochastic process, or are described by a chaotic rather than stochastic process. Next, higher-dimensional vectors are constructed from the time series of geomagnetic reversals, and correlation dimension is calculated for these higher-dimensional vectors to find out if the correlation dimension has a convergence limit as we increase the vector space dimension. If the convergence limit is revealed from the experimental dataset, then the geomagnetic reversals are chaotic rather than stochastic and are described by a system with limited number of degrees of freedom determined by the correlation dimension. If one expects to describe the geomagnetic dynamo by a low-order system of non-linear differential equations, the system should have a low

  8. John Deakin: Double Exposures

    Directory of Open Access Journals (Sweden)

    Paul Rousseau

    2015-11-01

    Full Text Available In this series of short films made by Jonathan Law, the art historian James Boaden, and the curator of The John Deakin Archive, Paul Rousseau, discuss the double-exposure images made by the photographer John Deakin (1912-1972 in the 1950s and 1960s. The films ask you, firstly, to look closely at the images being discussed. Each one begins with a sustained and intense shot of a single image before opening up to a wide-ranging discussion about Deakin, double exposures, and photography.

  9. Double arch mirror study

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  10. Double-Barred Galaxies

    OpenAIRE

    Erwin, Peter

    2009-01-01

    I present a brief review of what is known about double-barred galaxies, where a small ("inner") bar is nested inside a larger ("outer") bar; the review is focused primarily on their demographics and photometric properties. Roughly 20% of S0--Sb galaxies are double-barred; they may be rarer in later Hubble types. Inner bars are typically ~ 500 pc in radius (~ 12% the size of outer bars), but sizes range from ~ 100 pc to > 1 kpc. The structure of at least some inner bars appears very similar to...

  11. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used...

  12. Influence of PCL on mechanical properties and bioactivity of ZrO2-based hybrid coatings synthesized by sol-gel dip coating technique.

    Science.gov (United States)

    Catauro, Michelina; Bollino, Flavia; Veronesi, Paolo; Lamanna, Giuseppe

    2014-06-01

    The biological properties of medical implants can be enhanced through surface modifications such as to provide a firm attachment of the implant. In this study, organic-inorganic hybrid coatings have been synthesized via sol-gel dip coating. They consist of an inorganic ZrO2 matrix in which different amounts of poly(ε-caprolactone) have been entrapped to improve the mechanical properties of the films. The influence of the PCL amount on the microstructural, biological and mechanical properties of the coating has been investigated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses have shown that the hybrids used for the coating are homogenous and totally amorphous materials; Fourier transform infrared spectroscopy (FT-IR) has demonstrated that hydrogen bonds arise between the organic and inorganic phases. SEM and atomic force microscopy (AFM) have highlighted the nanostructured nature of the film. SEM and EDS analyses, after soaking the samples in a simulated body fluid (SBF), have pointed out the apatite formation on the coating surface, which proves the bone-bonding ability of the nanocomposite bioactive films. Scratch and nano-indentation tests have shown that the coating hardness, stiffness and Young's modulus decrease in the presence of large amounts of the organic phase. Copyright © 2014. Published by Elsevier B.V.

  13. Cross-cultural adaptation of the Posttraumatic Stress Disorder Checklist 5 (PCL-5) and Life Events Checklist 5 (LEC-5) for the Brazilian context.

    Science.gov (United States)

    Lima, Eduardo de Paula; Vasconcelos, Alina Gomide; Berger, William; Kristensen, Christian Haag; Nascimento, Elizabeth do; Figueira, Ivan; Mendlowicz, Mauro Vitor

    2016-01-01

    To describe the process of cross-cultural adaptation of the Posttraumatic Stress Disorder Checklist 5 (PCL-5) and the Life Events Checklist 5 (LEC-5) for the Brazilian sociolinguistic context. The adaptation process sought to establish conceptual, semantic, and operational equivalence between the original items of the questionnaire and their translated versions, following standardized protocols. Initially, two researchers translated the original version of the scale into Brazilian Portuguese. Next, a native English speaker performed the back-translation. Quantitative and qualitative criteria were used to evaluate the intelligibility of items. Five specialists compared the original and translated versions and assessed the degree of equivalence between them in terms of semantic, idiomatic, cultural and conceptual aspects. The degree of agreement between the specialists was measured using the content validity coefficient (CVC). Finally, 28 volunteers from the target population were interviewed in order to assess their level of comprehension of the items. CVCs for items from both scales were satisfactory for all criteria. The mean comprehension scores were above the cutoff point established. Overall, the results showed that the adapted versions' items had adequate rates of equivalence in terms of concepts and semantics. The translation and adaptation processes were successful for both scales, resulting in versions that are not only equivalent to the originals, but are also intelligible for the population at large.

  14. Sol-gel synthesis and characterization of SiO2/PCL hybrid materials containing quercetin as new materials for antioxidant implants.

    Science.gov (United States)

    Catauro, Michelina; Bollino, Flavia; Papale, Ferdinando; Piccolella, Simona; Pacifico, Severina

    2016-01-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing peri-implant disease onset. In this context quercetin, a naturally occurring flavonoid, has been entrapped, at different weight percentages in a silica/poly(ε-caprolactone)-based hybrid material by a sol-gel route. FT-IR and UV spectroscopic techniques were employed in order to characterize the hybrids. FT-IR analysis indicated changes in stretching frequencies of the quercetin dienonic moiety, suggesting that a flavonol oxidized derivative was formed during the sol-gel process. The establishment of hydrogen-bonded interactions between quercetin and silica and polymer matrices,was strongly affected by the amount of polymer. Poly(ε-caprolactone) did not interact with quercetin when it was loaded at high doses (50 wt.%). The morphology of the synthesized materials was observed by using SEM. The obtained images proved that the materials are hybrid nanocomposites. Their bioactivity was shown by the formation of a hydroxyapatite layer on samples' surface soaked in a fluid simulating the composition of the human plasma. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods and their cytotoxicity by the MTT assay. Data obtained revealed that the synthesized materials are biocompatible and that the hybrid system,with 6 wt.% of PCL and 15 wt.% of quercetin, produced the strongest antiradical efficacy.

  15. Novel star-type methoxy-poly(ethylene glycol) (PEG)-poly({epsilon}-caprolactone) (PCL) copolymeric nanoparticles for controlled release of curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Feng Runliang; Zhu Wenxia; Song Zhimei, E-mail: zhimei_song@126.com [University of Jinan, Shandong Academy of Medical Science, Department of Pharmaceutical Engineering, School of Medicine and Life Sciences (China); Zhao Liyan [Hebei North University, Department of Pharmacy (China); Zhai Guangxi [Shandong University, Department of Pharmaceutics, College of Pharmacy (China)

    2013-06-15

    To improve curcumin's (CURs) water solubility and release property, a novel star methoxy poly(ethylene glycol)-poly({epsilon}-caprolactone) (MPEG-PCL) copolymer was synthesized through O-alkylation, basic hydrolysis and ring-opening polymerization reaction with MPEG, epichlorohydrin, and {epsilon}-caprolactone as raw materials. The structure of the novel copolymer was characterized by {sup 1}H NMR, FT-IR, and GPC. The results of FT-IR and differential scanning calorimeter of CUR-loaded nanoparticles (NPs) prepared by dialysis method showed that CUR was successfully encapsulated into the SMP12 copolymeric NPs with 98.2 % of entrapment efficiency, 10.91 % of drug loading, and 88.4 {+-} 11.2 nm of mean particle diameter in amorphous forms. The dissolubility of nanoparticulate CUR was increased by 1.38 Multiplication-Sign 10{sup 5} times over CUR in water. The obtained blank copolymer showed no hemolysis. A sustained CUR release to a total of approximately 56.13 % was discovered from CUR-NPs in 40 % of ethanol saline solution within 72 h on the use of dialysis method. The release behavior fitted the ambiexponent and biphasic kinetics equation. In conclusion, the copolymeric NPs loading CUR might serve as a potential nanocarrier to improve the solubility and release property of CUR.

  16. Visual mislocalization during double-step saccades

    Directory of Open Access Journals (Sweden)

    Eckart eZimmermann

    2015-10-01

    Full Text Available Visual objects presented briefly at the time of saccade onset appear compressed toward the saccade target. Compression strength depends on the presentation of a visual saccade target signal and is strongly reduced during the second saccade of a double-step saccade sequence (Zimmermann et al., 2014; 2014. Here, I tested whether perisaccadic compression is linked to saccade planning by contrasting two double-step paradigms. In the same-direction double-step paradigm, subjects were required to perform two rightward 10° saccades successively. At various times around execution of the saccade sequence a probe dot was briefly flashed. Subjects had to localize the position of the probe dot after they had completed both saccades. I found compression of visual space only at the time of the first but not at the time of the second saccade. In the reverse-direction paradigm, subjects performed first a rightward 10° saccade followed by a leftward 10° saccade back to initial fixation. In this paradigm compression was found in similar magnitude during both saccades. Analysis of the saccade parameters did not reveal indications of saccade sequence preplanning in this paradigm. I therefore conclude that saccade planning, rather than saccade execution factors, is involved in perisaccadic compression.

  17. Aristotle and Double Effect

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2014-01-01

    There are some interesting similarities between Aristotle’s ‘mixed actions’ in Book III of the Nicomachean Ethics and the actions often thought to be justifiable with the Doctrine of Double Effect. Here I analyse these similarities by comparing Aristotle’s examples of mixed actions with standard ...

  18. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Abstract. The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given.

  19. Double-Glazing Interferometry

    Science.gov (United States)

    Toal, Vincent; Mihaylova, Emilia M.

    2009-01-01

    This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for…

  20. Double beta decay

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.; Picciotto, C.

    1978-01-01

    The problem of double beta decay is reviewed with emphasis on its relevance to lepton number conservation. Recently, the ratio of the double beta-decay half-lives of /sup 128/Te and /sup 130/Te has been measured in a geological experiment and a limit for the ratio of the neutrinoless rate to the total rate for /sup 82/Se decay has been obtained from a direct-detection experiment. For the first time, these results show conclusively that double beta decay is not primarily a lepton-number-violating neutrinoless process. However, they also do not agree with calculations which assume that only lepton-number-conserving two-neutrino double beta decay occurs. The conclusion that lepton number conservation is violated is suggested by limited experimental information. By considering contributions to the total rate from both the two-neutrino and the neutrinoless channels, we obtain data which are consistent with a lepton nonconservation parameter of order eta=3.5 x 10/sup -5/. Roughly the same value of eta is obtained by assuming that the decay occurs either via lepton emission from two nucleons or via emission from a resonance in the nucleus.

  1. Design for Double Rainbow

    Science.gov (United States)

    Thomas, Lisa Carlucci

    2011-01-01

    Rare is the inspirational, spontaneous, transformative moment shared among 20 million people. In the summer of 2010, people around the world were moved by the sighting of a double rainbow--almost a triple rainbow--"all the way across the sky" in Yosemite National Park. Caught on video and posted to by YouTube by Paul Vasquez in January 2010, the…

  2. Generalizing double graphs

    Directory of Open Access Journals (Sweden)

    Zagaglia Salvi, Norma

    2007-10-01

    Full Text Available In this paper we study the graphs which are direct product of a simple graph G with the graphs obtained by the complete graph Kk adding a loop to each vertex; thus these graphs turn out to be a generalization of the double graphs.

  3. Hybrid Double Quantum Dots

    DEFF Research Database (Denmark)

    Sherman, D.; Yodh, J. S.; Albrecht, S. M.

    2016-01-01

    Epitaxial semiconductor-superconductor hybrid materials are an excellent basis for studying mesoscopic and topological superconductivity, as the semiconductor inherits a hard superconducting gap while retaining tunable carrier density. Here, we investigate double-quantum-dot devices made from InA...... that the individual dots host weakly hybridized Majorana modes....

  4. Efficacy of rhBMP-2 loaded PCL/PLGA/β-TCP guided bone regeneration membrane fabricated by 3D printing technology for reconstruction of calvaria defects in rabbit.

    Science.gov (United States)

    Shim, Jin-Hyung; Yoon, Min-Chul; Jeong, Chang-Mo; Jang, Jinah; Jeong, Sung-In; Cho, Dong-Woo; Huh, Jung-Bo

    2014-11-10

    We successfully fabricated a three-dimensional (3D) printing-based PCL/PLGA/β-TCP guided bone regeneration (GBR) membrane that slowly released rhBMP-2. To impregnate the GBR membrane with intact rhBMP-2, collagen solution encapsulating rhBMP-2 (5 µg ml(-1)) was infused into pores of a PCL/PLGA/β-TCP membrane constructed using a 3D printing system with four dispensing heads. In a release profile test, sustained release of rhBMP-2 was observed for up to 28 d. To investigate the efficacy of the GBR membrane on bone regeneration, PCL/PLGA/β-TCP membranes with or without rhBMP-2 were implanted in an 8 mm calvaria defect of rabbits. Bone formation was evaluated at weeks 4 and 8 histologically and histomorphometrically. A space making ability of the GBR membrane was successfully maintained in both groups, and significantly more new bone was formed at post-implantation weeks 4 and 8 by rhBMP-2 loaded GBR membranes. Interestingly, implantation with rhBMP-2 loaded GBR membranes led to almost entire healing of calvaria defects within 8 weeks.

  5. [Personality disorders and "psychopathy" in sex offenders imprisoned in forensic-psychiatric hospitals--SKID-II- and PCL-R-results in patients with impulse control disorder and paraphilia].

    Science.gov (United States)

    Borchard, Bernd; Gnoth, Annika; Schulz, Wolfgang

    2003-04-01

    In order to clarify differential-diagnostic questions 47 mentally ill sex offenders (with impulse control disorder and paraphilia) were assessed with regard to comorbidity of personality disorders and "psychopathy". For this examination the SKID-II for personality disorders and the Psychopathy Checklist (PCL-R) were used. 72 % of the sex offenders showed at least one personality disorder. The highest prevalence was found for cluster-B disorders, first of all the antisocial personality disorder. Using a PCL-R cut off score of 25 (for Europe) 10 of the 47 subjects (21 %) were diagnosed as "psychopaths", whereas being a "psychopath" is associated with a number of different personality disorders. The importance of structured diagnostic with regard to comorbidity of personality disorders in sex offenders imprisoned in maximum security psychiatric hospitals is stressed, and furthermore there is evidence that the PCL-R is a valid instrument for prognosis, but not a psychological-psychiatric instrument for the assessment of personality disorders.

  6. The fidelity of reverse transcription differs in reactions primed with RNA versus DNA primers

    NARCIS (Netherlands)

    Oude Essink, B. B.; Berkhout, B.

    1999-01-01

    Reverse transcriptase enzymes (RT) convert single-stranded retroviral RNA genomes into double-stranded DNA. The RT enzyme can use both RNA and DNA primers, the former being used exclusively during initiation of minus- and plus-strand synthesis. Initiation of minus-strand DNA synthesis occurs by

  7. Vasectomy reversal: a clinical update

    Directory of Open Access Journals (Sweden)

    Abhishek P Patel

    2016-01-01

    Full Text Available Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

  8. Reverse Transcription Mechanically Initiates HIV-1 Capsid Disassembly.

    Science.gov (United States)

    Rankovic, Sanela; Varadarajan, Janani; Ramalho, Ruben; Aiken, Christopher; Rousso, Itay

    2017-06-15

    The HIV-1 core consists of the viral genomic RNA and several viral proteins encased within a conical capsid. After cell entry, the core disassembles in a process termed uncoating. Although HIV-1 uncoating has been linked to reverse transcription of the viral genome in target cells, the mechanism by which uncoating is initiated is unknown. Using time-lapse atomic force microscopy, we analyzed the morphology and physical properties of isolated HIV-1 cores during the course of reverse transcription in vitro We found that, during an early stage of reverse transcription the pressure inside the capsid increases, reaching a maximum after 7 h. High-resolution mechanical mapping reveals the formation of a stiff coiled filamentous structure underneath the capsid surface. Subsequently, this coiled structure disappears, the stiffness of the capsid drops precipitously to a value below that of a pre-reverse transcription core, and the capsid undergoes partial or complete rupture near the narrow end of the conical structure. We propose that the transcription of the relatively flexible single-stranded RNA into a more rigid filamentous structure elevates the pressure within the core, which triggers the initiation of capsid disassembly.IMPORTANCE For successful infection, the HIV-1 genome, which is in the form of a single-stranded RNA enclosed inside a capsid shell, must be reverse transcribed into double-stranded DNA and released from the capsid (in a process known as uncoating) before it can be integrated into the target cell genome. The mechanism that triggers uncoating is a pivotal question of long standing. By using atomic force microscopy, we found that during reverse transcription the pressure inside the capsid increases until the internal stress exceeds the strength of the capsid structure and the capsid breaks open. The application of AFM technologies to study purified HIV-1 cores represents a new experimental platform for elucidating additional aspects of capsid

  9. Thermally driven microfluidic pumping via reversible shape memory polymers

    Science.gov (United States)

    Robertson, J. M.; Rodriguez, R. X.; Holmes, L. R., Jr.; Mather, P. T.; Wetzel, E. D.

    2016-08-01

    The need exists for autonomous microfluidic pumping systems that utilize environmental cues to transport fluid within a network of channels for such purposes as heat distribution, self-healing, or optical reconfiguration. Here, we report on reversible thermally driven microfluidic pumping enabled by two-way shape memory polymers. After developing a suitable shape memory polymer (SMP) through variation in the crosslink density, thin and flexible microfluidic devices were constructed by lamination of plastic films with channels defined by laser-cutting of double-sided adhesive film. SMP blisters integrated into the devices provide thermally driven pumping, while opposing elastic blisters are used to generate backpressure for reversible operation. Thermal cycling of the device was found to drive reversible fluid flow: upon heating to 60 °C, the SMP rapidly contracted to fill the surface channels with a transparent fluid, and upon cooling to 8 °C the flow reversed and the channel re-filled with black ink. Combined with a metallized backing layer, this device results in refection of incident light at high temperatures and absorption of light (at the portions covered with channels) at low temperatures. We discuss power-free, autonomous applications ranging from thermal regulation of structures to thermal indication via color change.

  10. Reverse innovation in maternal health.

    Science.gov (United States)

    Firoz, Tabassum; Makanga, Prestige Tatenda; Nathan, Hannah L; Payne, Beth; Magee, Laura A

    2017-09-01

    Reverse innovation, defined as the flow of ideas from low- to high-income settings, is gaining traction in healthcare. With an increasing focus on value, investing in low-cost but effective and innovative solutions can be of mutual benefit to both high- and low-income countries. Reverse innovation has a role in addressing maternal health challenges in high-income countries by harnessing these innovative solutions for vulnerable populations especially in rural and remote regions. In this paper, we present three examples of 'reverse innovation' for maternal health: a low-cost, easy-to-use blood pressure device (CRADLE), a diagnostic algorithm (mini PIERS) and accompanying mobile app (PIERS on the Move), and a novel method for mapping maternal outcomes (MOM).

  11. Anomalous photo-induced response by double-pulse excitation in the organic conductor (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-ya

    2009-02-01

    We measured ultrafast reflectivity changes induced by double-pulse excitation in the organic conductor (EDO-TTF)2PF6. Using double-pulse excitation with a relatively high intensity, the sign of reflectivity change became reversed at around 0.8 ps and subsequently the reflectivity change reverted to that of the normal photo-induced state after about 1 ps. Using a optically phase-locked double-pulse with low intensity, we found that the temporal profile excited by an in-phase double-pulse differs from that by an out-of-phase double-pulse despite the time difference between the double-pulses being only 1.31 fs. This was true even when there is almost no overlap between each pulse in the double-pulse. These results indicate that the photo-response in this material to double-pulse excitation differs greatly from the linear sum of the responses to single pulses.

  12. MRI reveals reversible lesions resembling posterior reversible encephalopathy in porphyria

    Energy Technology Data Exchange (ETDEWEB)

    Celik, M. [Huesrev Gerede c, 128/4 Tesvikiye, 80690 Istanbul (Turkey); Department of Neurology, Sisli Etfal Education and Research Hospital, Sisli Etfal S., Sisli, Istanbul (Turkey); Forta, H.; Babacan, G. [Department of Neurology, Sisli Etfal Education and Research Hospital, Sisli Etfal S., Sisli, Istanbul (Turkey); Dalkilic, Tuerker [Department of Neurosurgery, Sisli Etfal Education and Research Hospital, Sisli Etfal S., Sisli, Istanbul (Turkey)

    2002-10-01

    We report a 20-year-old woman who had an attack of acute intermittent porphyria with seizures, hallucinations, autonomic and somatic neuropathy. T2-weighted MRI revealed multiple lesions which were no longer visible 3 months later. We suggest a similar mechanism to posterior reversible encephalopathy underlying cerebral symptoms in porphyria. (orig.)

  13. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...... be the starting point of a computational theory of reversible computing. We provide a novel semantics-based approach to such a theory, using reversible Turing machines (RTMs) as the underlying computation model. We show that the RTMs can compute exactly all injective, computable functions. We find that the RTMs...

  14. Reference counting for reversible languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2014-01-01

    Modern programming languages and operating systems use heap memory that allows allocation and deallocation of memory to be decoupled, so they don't follow a stack discipline. Axelsen and Glück have presented a reversible heap manager where allocation and deallocation are each other's logical...... inverses: Freeing a block of memory is done by running the allocation procedure backwards. Axelsen and Glück use this heap manager to sketch implementation of a simple reversible functional language where pattern matching a constructor is the inverse of construction, so pattern-matching implies...

  15. Stagnation point reverse flow combustor

    Science.gov (United States)

    Zinn, Ben T. (Inventor); Neumeier, Yedidia (Inventor); Seitzman, Jerry M. (Inventor); Jagoda, Jechiel (Inventor); Weksler, Yoav (Inventor)

    2008-01-01

    A method for combusting a combustible fuel includes providing a vessel having an opening near a proximate end and a closed distal end defining a combustion chamber. A combustible reactants mixture is presented into the combustion chamber. The combustible reactants mixture is ignited creating a flame and combustion products. The closed end of the combustion chamber is utilized for directing combustion products toward the opening of the combustion chamber creating a reverse flow of combustion products within the combustion chamber. The reverse flow of combustion products is intermixed with combustible reactants mixture to maintain the flame.

  16. Marburg Virus Reverse Genetics Systems

    Directory of Open Access Journals (Sweden)

    Kristina Maria Schmidt

    2016-06-01

    Full Text Available The highly pathogenic Marburg virus (MARV is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  17. Reversible Multiparty Sessions with Checkpoints

    Directory of Open Access Journals (Sweden)

    Mariangiola Dezani-Ciancaglini

    2016-08-01

    Full Text Available Reversible interactions model different scenarios, like biochemical systems and human as well as automatic negotiations. We abstract interactions via multiparty sessions enriched with named checkpoints. Computations can either go forward or roll back to some checkpoints, where possibly different choices may be taken. In this way communications can be undone and different conversations may be tried. Interactions are typed with global types, which control also rollbacks. Typeability of session participants in agreement with global types ensures session fidelity and progress of reversible communications.

  18. Applications of Diamonded Double Negation

    OpenAIRE

    Yli-Jyrä, Anssi

    2008-01-01

    Nested complementation plays an important role in expressing counter- i.e. star-free and first-order definable languages and their hierarchies. In addition, methods that compile phonological rules into finite-state networks use double-nested complementation or “double negation”. This paper reviews how the double-nested complementation extends to a relatively new operation, generalized restriction (GR), coined by the author (Yli-Jyrä and Koskenniemi 2004). This operation encapsulates a double-...

  19. Double Cortex Syndrome

    OpenAIRE

    J Gordon Millichap

    1999-01-01

    The incidence of mutations in the X-linked gene doublecortin in patients with “double cortex” syndrome (DC; also called subcortical band heterotopia or laminar heterotopia) and familial DC with lissencephaly was investigated in a cohort of 8 pedigrees and 47 sporadic patients with DC examined at the Division of Neurogenics, Beth Israel Deaconess Medical Center, Boston, and multiple centers in the US and abroad.

  20. Algebra of Majorana doubling.

    Science.gov (United States)

    Lee, Jaehoon; Wilczek, Frank

    2013-11-27

    Motivated by the problem of identifying Majorana mode operators at junctions, we analyze a basic algebraic structure leading to a doubled spectrum. For general (nonlinear) interactions the emergent mode creation operator is highly nonlinear in the original effective mode operators, and therefore also in the underlying electron creation and destruction operators. This phenomenon could open up new possibilities for controlled dynamical manipulation of the modes. We briefly compare and contrast related issues in the Pfaffian quantum Hall state.

  1. Results of double contrast enema

    Energy Technology Data Exchange (ETDEWEB)

    Czembirek, H.; Sommer, G.; Wittich, G.; Tscholakoff, D.; Salomonowitz, E.

    1983-07-01

    Experiences and results of double contrast enemas are reported. The accuracy of double contrast enemas is proved by 500 consecutive investigations. Correlation of endoscopic and roentgenologic investigations showed, that the double contrast enema is a reliable method concerning the detection of polyps, carcinomas and inflammatory colon diseases. Advantages and disadvantages of roentgenology and endoscopy of the colon are discussed.

  2. Reversible logic gate using adiabatic superconducting devices.

    Science.gov (United States)

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-09-15

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage.

  3. Strengths and limitations of actuarial prediction of criminal reoffence in a German prison sample: a comparative study of LSI-R, HCR-20 and PCL-R.

    Science.gov (United States)

    Dahle, Klaus-Peter

    2006-01-01

    Unlike many other countries, for many years, Germany disregarded structured instruments for assessing the risk of criminal reoffence. However, this negative attitude now seems to be gradually changing. An increasing number of contributions regarding structured instruments have been published in the German literature in the last years, and some instruments have already found their way into practice. However, studies that systematically examine the applicability of the mostly Anglo-American instruments to German criminals are still lacking. Therefore, the major objective of the current study was to test some internationally established procedures in a larger unselected sample from the German penal system. The following were included in the study: the Level of Service Inventory - Revised (LSI-R), the HCR-20 Scheme, and the Psychopathy Checklist - Revised (PCL-R). On the whole, the instruments proved to be applicable to German criminals with only a few adaptations to the German situation, and they achieved a predictive accuracy comparable to the values reported internationally. However, there were only minor differences in the predictive performance between the measures. Moreover, some basic limitations became apparent. Firstly, we found quite high percentages of criminals with medium scores and a correspondingly ambiguous prognosis. Furthermore, the predictive accuracy seemed to be dependent on demographic, criminological and psychopathological characteristics of the offenders. Finally, the instruments appeared to only partially utilize the empirical store of knowledge available regarding factors influencing the recidivism of criminals, since even a simple predictive model that only added a few further aspects besides the tested instruments (e. g. treatment yes or no) achieved systematically better predictions than the instruments alone. Altogether, the tested measures turned out to be useful instruments for risk assessments and may be conducive for a more systemized

  4. AS1411 aptamer and folic acid functionalized pH-responsive ATRP fabricated pPEGMA-PCL-pPEGMA polymeric nanoparticles for targeted drug delivery in cancer therapy.

    Science.gov (United States)

    Lale, Shantanu V; R G, Aswathy; Aravind, Athulya; Kumar, D Sakthi; Koul, Veena

    2014-05-12

    Nonspecificity and cardiotoxicity are the primary limitations of current doxorubicin chemotherapy. To minimize side effects and to enhance bioavailability of doxorubicin to cancer cells, a dual-targeted pH-sensitive biocompatible polymeric nanosystem was designed and developed. An ATRP-based biodegradable triblock copolymer, poly(poly(ethylene glycol) methacrylate)-poly(caprolactone)-poly(poly(ethylene glycol) methacrylate) (pPEGMA-PCL-pPEGMA), conjugated with doxorubicin via an acid-labile hydrazone bond was synthesized and characterized. Dual targeting was achieved by attaching folic acid and the AS1411 aptamer through EDC-NHS coupling. Nanoparticles of the functionalized triblock copolymer were prepared using the nanoprecipitation method, resulting in an average particle size of ∼140 nm. The biocompatibility of the nanoparticles was evaluated using MTT cytotoxicity assays, blood compatibility studies, and protein adsorption studies. In vitro drug release studies showed a higher cumulative doxorubicin release at pH 5.0 (∼70%) compared to pH 7.4 (∼25%) owing to the presence of the acid-sensitive hydrazone linkage. Dual targeting with folate and the AS1411 aptamer increased the cancer-targeting efficiency of the nanoparticles, resulting in enhanced cellular uptake (10- and 100-fold increase in uptake compared to single-targeted NPs and non-targeted NPs, respectively) and a higher payload of doxorubicin in epithelial cancer cell lines (MCF-7 and PANC-1), with subsequent higher apoptosis, whereas a normal (noncancerous) cell line (L929) was spared from the adverse effects of doxorubicin. The results indicate that the dual-targeted pH-sensitive biocompatible polymeric nanosystem can act as a potential drug delivery vehicle against various epithelial cancers such as those of the breast, ovary, pancreas, lung, and others.

  5. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  6. Reversibility of chronic airflow obstruction

    NARCIS (Netherlands)

    Postma, Dirkje Sjoukje

    1984-01-01

    This thesis deals with variations in airway diameter in patients with chronic, partly reversible airflow obstruction. The patients studied in this thesis have been addressed in the literature with terms as CAO, COPD, CNSLD. The confusion caused by combining patients in one descriptive term, e.g.

  7. Vasectomy reversal : a clinical update

    NARCIS (Netherlands)

    A.P. Patel (Abhishek); R.P. Smith (Ryan)

    2016-01-01

    textabstractVasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage,

  8. A Framework for Reverse Logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2003-01-01

    textabstractReverse Logistics has been stretching out worldwide, involving all the layers of supply chains in various industry sectors. While some actors in the chain have been forced to take products back, others have pro-actively done so, attracted by the value in used products One way or the

  9. Sex determination and sex reversal.

    Science.gov (United States)

    Camerino, Giovanna; Parma, Pietro; Radi, Orietta; Valentini, Stella

    2006-06-01

    Sex determination in mammals is based on a genetic cascade that controls the fate of the gonads. Gonads will then direct the establishment of phenotypic sex through the production of hormones. Different types of sex reversal are expected to occur if mutations disrupt one of the three steps of gonadal differentiation: formation of the gonadal primordia, sex determination, and testis or ovary development.

  10. Reversible blindness in fulminating preeclampsia

    African Journals Online (AJOL)

    blindness can be due to involvement of the occipital cortex or the retina. Although very alarming, this type of blindness is usually reversible following appropriate management of such patients. Here we present the case of a woman in whom fulminating preeclampsia was complicated by blindness. Fundoscopic findings were ...

  11. Cobalt double-ring and double-dot structures: Magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    López-Urías, F., E-mail: flo@ipicyt.edu.mx [Advanced Materials Department, IPICYT, Camino a la presa San José 2055, Col. Lomas 4a sección, 78216, San Luis Potosí S.L.P., México (Mexico); Torres-Heredia, J.J. [Instituto Tecnológico Superior de Las Choapas, Col. J. M. Rosa do, 96980, Las Choapas, Veracruz (Mexico); Muñoz-Sandoval, E. [Advanced Materials Department, IPICYT, Camino a la presa San José 2055, Col. Lomas 4a sección, 78216, San Luis Potosí S.L.P., México (Mexico)

    2016-02-15

    The magnetization reversal mechanism of nanostructures of cobalt double-rings (D-rings) and double-dots (D-dots) is investigated in the framework of micromagnetic simulations. The arrays contain two identical coupled rings (wide and narrow) or dots with outer diameter of 200 nm and thicknesses ranging from 2–20 nm. Hysteresis loops, dipole–dipole and exchange energies are systematically calculated for the cases of the structures touching and the structures with a 50-nm inter-magnet separation; moreover, magnetization states along the hysteresis curve are analyzed. The results of both dot and ring D-magnets are compared with the corresponding individual magnets. Our results reveal that all D-ring (in contact and separated) arrays containing narrow rings exhibit non-null remanent magnetization; furthermore, higher coercive fields are promoted when the magnet thickness is increased. It is observed that the magnetization reversal is driven mainly by a clockwise rotation of onion-states, followed by states of frustrated vortices. Our results could help improve the understanding of the magnetic interactions in nanomagnet arrays.

  12. Reversible simulations of elastic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Perumalla, Kalyan S.; Protopopescu, Vladimir A.

    2013-05-01

    Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, \\textit{with essentially no memory overhead}. The challenge in achieving reversibility for an n-particle collision (where, in general, n<< N) arises from the presence of nd-d-1 degrees of freedom (arbitrary angles) during each collision, as well as from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom (angles) during the forward simulation must be tracked. This requires memory proportional to the number of collisions, which grows very fast with N and d, thereby severely limiting the \\textit{de facto} applicability of the scheme. This limitation is addressed here by first performing a pseudo-randomization of angles, which ensures determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed which correctly samples the constrained phase space. Upon combining the pseudo-randomization with correct phase space sampling, perfect reversibility of collisions is achieved, as illustrated for n<=3, d=2, and n=2, d=3. This result enables, for the first time, reversible simulations of elastic collisions with essentially zero memory accumulation. In principle, the approach presented here could be generalized to larger values of n, which would be of definite interest for molecular dynamics simulations at high densities.

  13. Ac-induced disruption of the doubleDs structure in tomato

    NARCIS (Netherlands)

    Rommens, Caius M.T.; Biezen, Erik A. van der; Ouwerkerk, Pieter B.F.; Nijkamp, H. John J.; Hille, Jacques

    1991-01-01

    The maize doubleDs element is stably maintained in the tomato genome. Upon the subsequent introduction of Ac into a plant containing doubleDs, disruption of the doubleDs structure and DNA rearrangements at the site of the doubleDs element were observed. No indications were obtained for excision of

  14. Color dissociation artifacts in double Maddox rod cyclodeviation testing.

    Science.gov (United States)

    Simons, K; Arnoldi, K; Brown, M H

    1994-12-01

    The double Maddox rod test, based on a red Maddox rod in front of one eye and a clear Maddox rod in front of the other, is used to measure cyclodeviation, typically in patients with superior oblique muscle pareses. Discrepant results between the double Maddox rod test and other torsion measures, and reports of "paradoxic" cyclodeviation in the normal eye of some patients with superior oblique paresis, suggest the two-color format of the double Maddox rod test may produce artifactual torsion measures. Forty patients with superior oblique paresis were tested twice using the double Maddox rod test, reversing the red and white Maddox rods between eyes for the second test, and 18 were tested further with same-color red or clear Maddox rods in front of both eyes. With the standard double Maddox rod test, 33 (83%) of 40 patients localized their cyclodeviation to the eye viewing through the red Maddox rod, irrespective of laterality of the paresis or fixation preference. In all 33 patients, laterality of the perceived torsion changed between eyes when testing was repeated with red and white Maddox rods interchanged between eyes. With same-color Maddox rods before both eyes, 17 (94%) of 18 patients localized extorsion to the paretic eye. There was 7.6:1 ratio of luminance transmission and a 1.6:1 ratio of grating spatial frequency bandpass in the plano meridian between the clear and red Maddox rods, which appear to be responsible for the double Maddox rod test artifact. The traditional double Maddox rod test may produce artifactual cyclodeviation measurements. An alternative version of the test, based on same-color Maddox rods in front of both eyes, is proposed. The relatively high spatial frequency bandpass characteristics of the plano meridian of the Maddox rod (as high as 20/25 Snellen equivalent resolution through the clear Maddox rod) also suggests double Maddox rod testing should be conducted in a dark room to avoid biases from visual environment cues.

  15. The Double Star mission

    Directory of Open Access Journals (Sweden)

    Liu

    2005-11-01

    Full Text Available The Double Star Programme (DSP was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer", was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC in Beijing and the European Payload Operations Service (EPOS at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

  16. Layered double hydroxides

    DEFF Research Database (Denmark)

    López Rayo, Sandra; Imran, Ahmad; Hansen, Hans Chr. Bruun

    2017-01-01

    A novel zinc (Zn) fertilizer concept based on Zn doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthetized, their chemical composition was analyzed and their nutrient release was studied in buffered solutions with different pH values. Uptake...... the long-term Zn release capacity of LDHs complying with a release-on-demand behavior and serves as proof-of-concept that Zn-doped Mg-Fe-LDHs can be used as Zn fertilizers....

  17. A functional language for describing reversible logic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    Reversible logic is a computational model where all gates are logically reversible and combined in circuits such that no values are lost or duplicated. This paper presents a novel functional language that is designed to describe only reversible logic circuits. The language includes high....... Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...

  18. Reversible Watermarking Using Statistical Information

    Directory of Open Access Journals (Sweden)

    Kurugollu Fatih

    2010-01-01

    Full Text Available In most reversible watermarking methods, a compressed location map is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.

  19. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    INTRODUCTION: A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients. MATERIAL AND METHODS: The medical records...... of all patients who underwent reversal of a colostomy after a primary Hartmann's procedure during the period May 2005 to December 2008 were reviewed retrospectively in a case-control study. RESULTS: A total of 43 patients were included. Twenty-one had a laparoscopic and 22 an open procedure. The two...... groups matched with regard to age, sex, American Society of Anestheologists (ASA) score, body mass index and indication for Hartmann's operation. A significantly longer operation time was found for laparoscopic than for open surgery (median 285 versus 158 minutes, p

  20. Reverse osmosis water purification system

    Science.gov (United States)

    Ahlstrom, H. G.; Hames, P. S.; Menninger, F. J.

    1986-01-01

    A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water.

  1. Double conjugate laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Daunt, G.H.

    1991-01-29

    This paper describes a double conjugate laser amplifier system for producing a stable output laser beam in line with a laser oscillator input beam. It comprises: a laser oscillator which produces a low energy oscillator laser beam therefrom directly along a laser beam axis of the system; an amplification means comprised of double conjugate laser amplifiers further comprised of a first and a second singly phase conjugate amplifiers laterally opposite each other about the laser beam axis; polarizers with one of the polarizers positioned between each of the first and second singly phase conjugate amplifiers on the laser beam axis; Pockels cells with on of the Pockels cells positioned on the laser beam axis immediately prior to one of the polarizers; and a means for selectively switching the amplifier means comprised of applying a half-wave voltage at each of the Pockels cells to provide a polarization rotation of the input beam through 90{degrees} for routing of the oscillator laser beam directly through or reflected off the polarizes as an input beam to the amplification means wherein the amplification means amplifies the input beam twice in each of the first and second singly phase conjugate amplifiers and reflects the amplified laser beam off the polarizers as an amplified laser output beam in exactly the same direction as the input laser beam.

  2. [Process of HIV-1 reverse transcription and its detection by using PCR].

    Science.gov (United States)

    Yao, Wen-Xue; Wu, Ying-Liang; Guo, Ying

    2008-02-01

    Human immunodeficiency virus (HIV) is a retrovirus, belongs to Lentiviridae family. As long as viral genetic material entering into host cytoplasm, double-strand DNAs synthesis occurs which is catalyzed by reverse transcriptase (RT) with viral plus-strand RNA as template. This reverse transcription is a key link of HIV-1 life cycle and an important target for anti-HIV drug development. The process of reverse transcription can be divided into several steps: formation of minus-strand strong-stop DNA; the first translocation; initiation of plus-strand DNA synthesis; and, the second translocation and the completion of both strands. These steps can be detected individually by using polymerase chain reaction (PCR) according to the amplified products on the region of R/U5, U3, U5/PBS and the sequence between LTR and Gag. In this review, we summarize the principle for detecting stages of HIV-1 reverse transcription by using PCR.

  3. A Generalized Reverse Jacket Transform

    OpenAIRE

    Lee, Moon Ho; Rajan, Sundar B; Park, JY

    2001-01-01

    Generalization of the well-known Walsh-Hadamard transform (WHT), namely center-weighted Hadamard transform (CWHT) and complex reverse-jacket transform (CRJT) have been proposed and their fast implementation and simple index generation algorithms have recently been reported. These transforms are of size 2(r) x 2(r) for integral values or r, and defined in terms of binary radix representation of integers. In this paper, using appropriate mixed-radix representation of integers, we present a gene...

  4. Reversible Destruction of Dynamical Localization

    OpenAIRE

    Lignier, Hans; Chabé, Julien; Delande, Dominique; Garreau, Jean Claude; Szriftgiser, Pascal

    2005-01-01

    4 pages, 2 eps figures (color); Dynamical localization is a localization phenomenon taking place, for example, in the quantum periodically-driven kicked rotor. It is due to subtle quantum destructive interferences and is thus of intrinsic quantum origin. It has been shown that deviation from strict periodicity in the driving rapidly destroys dynamical localization. We report experimental results showing that this destruction is partially reversible when the deterministic perturbation that des...

  5. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2013-12-01

    Full Text Available As the power of consumers is growing, the product return for customer service and customer retention has become a common practice in the competitive market, which propels the recent practice of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle. Reverse logistics is the flow and management of products, packaging, components and information from the point of consumption to the point of origin. It is a collection of practices similar to those of supply chain management, but in the opposite direction, from downstream to upstream. It involves activities such as reuse, repair, remanufacture, refurbish, reclaim and recycle. For the conventional forward logistics systems, the flow starts upstream as raw materials, later as manufactured parts and components to be assembled and continues downstream to reach customers as final products to be disposed once they reach their economic or useful lives. In reverse logistics, the disposed products are pushed upstream to be repaired, remanufactured, refurbished, and disassembled into components to be reused or as raw material to be recycled for later use.

  6. Time order reversals and saccades.

    Science.gov (United States)

    Kresevic, Jesse L; Marinovic, Welber; Johnston, Alan; Arnold, Derek H

    2016-08-01

    Ballistic eye movements, or saccades, present a major challenge to the visual system. They generate a rapid blur of movement across the surface of the retinae that is rarely consciously seen, as awareness of input is suppressed around the time of a saccade. Saccades are also associated with a number of perceptual distortions. Here we are primarily interested in a saccade-induced illusory reversal of apparent temporal order. We examine the apparent order of transient targets presented around the time of saccades. In agreement with previous reports, we find evidence for an illusory reversal of apparent temporal order when the second of two targets is presented during a saccade - but this is only apparent for some observers. This contrasts with the apparent salience of targets presented during a saccade, which is suppressed for all observers. Our data suggest that separable processes might underlie saccadic suppressions of salience and saccade-induced reversals of apparent order. We suggest the latter arises when neural transients, normally used for timing judgments, are suppressed due to a saccade - but that this is an insufficient pre-condition. We therefore make the further suggestion, that the loss of a neural transient must be coupled with a specific inferential strategy, whereby some people assume that when they lack a clear impression of event timing, that event must have happened less recently than alternate events for which they have a clear impression of timing. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  7. Modification of Ti6Al4V implant surfaces by biocompatible TiO2/PCL hybrid layers prepared via sol-gel dip coating: Structural characterization, mechanical and corrosion behavior.

    Science.gov (United States)

    Catauro, Michelina; Bollino, Flavia; Giovanardi, Roberto; Veronesi, Paolo

    2017-05-01

    Surface modification of metallic implants is a promising strategy to improve tissue tolerance, osseointegration and corrosion resistance of them. In the present work, bioactive and biocompatible organic-inorganic hybrid coatings were prepared using a sol-gel dip coating route. They consist of an inorganic TiO 2 matrix in which different percentages of poly(ε-caprolactone) (PCL), a biodegradable and biocompatible polymer, were incorporated. The coatings were used to modify the surface of Ti6Al4V substrates in order to improve their wear and corrosion resistance. The chemical structure of the coatings was analyzed by attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy. Coating microstructure, mechanical properties and ability to inhibit the corrosion of the substrates were evaluated as a function of the PCL amount. Scanning electron microscopy (SEM) showed that the polymer allows to obtain crack-free coatings, but when high percentages were added uncoated areas appear. Nano-indentation tests revealed that, as expected, surface hardness and elastic modulus decrease as the percentage of polymeric matrix increases, but scratch testing demonstrated that the coatings are effective in preventing scratching of the underlying metallic substrate, at least for PCL contents up to 20wt%. The electrochemical tests (polarization curves acquired in order to evaluate the corrosion resistance) allowed to asses that the coatings have a significant effect in term of corrosion potential (E corr ) but they do not significantly affect the passivation process that titanium undergoes in contact with the test solution used (modified Dulbecco's phosphate-buffered saline or DPBS). Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Tissue-Engineered Small Diameter Arterial Vascular Grafts from Cell-Free Nanofiber PCL/Chitosan Scaffolds in a Sheep Model.

    Directory of Open Access Journals (Sweden)

    Takuma Fukunishi

    Full Text Available Tissue engineered vascular grafts (TEVGs have the potential to overcome the issues faced by existing small diameter prosthetic grafts by providing a biodegradable scaffold where the patient's own cells can engraft and form functional neotissue. However, applying classical approaches to create arterial TEVGs using slow degrading materials with supraphysiological mechanical properties, typically results in limited host cell infiltration, poor remodeling, stenosis, and calcification. The purpose of this study is to evaluate the feasibility of novel small diameter arterial TEVGs created using fast degrading material. A 1.0mm and 5.0mm diameter TEVGs were fabricated with electrospun polycaprolactone (PCL and chitosan (CS blend nanofibers. The 1.0mm TEVGs were implanted in mice (n = 3 as an unseeded infrarenal abdominal aorta interposition conduit., The 5.0mm TEVGs were implanted in sheep (n = 6 as an unseeded carotid artery (CA interposition conduit. Mice were followed with ultrasound and sacrificed at 6 months. All 1.0mm TEVGs remained patent without evidence of thrombosis or aneurysm formation. Based on small animal outcomes, sheep were followed with ultrasound and sacrificed at 6 months for histological and mechanical analysis. There was no aneurysm formation or calcification in the TEVGs. 4 out of 6 grafts (67% were patent. After 6 months in vivo, 9.1 ± 5.4% remained of the original scaffold. Histological analysis of patent grafts demonstrated deposition of extracellular matrix constituents including elastin and collagen production, as well as endothelialization and organized contractile smooth muscle cells, similar to that of native CA. The mechanical properties of TEVGs were comparable to native CA. There was a significant positive correlation between TEVG wall thickness and CD68+ macrophage infiltration into the scaffold (R2 = 0.95, p = 0.001. The fast degradation of CS in our novel TEVG promoted excellent cellular infiltration and neotissue

  9. A gecko-inspired double-sided adhesive.

    Science.gov (United States)

    Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

    2013-12-21

    Geckos' outstanding abilities to adhere to various surfaces are widely credited to the large actual contact areas of the fibrillar and hierarchical structures on their feet. These special features regulate the essential structural compliance for every attachment and thus provide robust yet reversible adhesions. Inspired by gecko's feet and our commonly used double-faced tape, we have successfully fabricated a gecko-inspired double-sided dry adhesive by using porous anodic alumina template assisted nano-wetting on a stiff polymer. It was determined that the obtained 2-sided structure showed largely decreased effective stiffness compared with its 1-sided counterpart, which favored better compliance and interfacial integrity. We also demonstrated that the repeatable double-sided adhesive improved the macroscopic normal and shear adhesion capacities over the widely-studied 1-side structure by ~50% and ~85%, respectively. By using the synthetic double-sided adhesive, the usage of traditional pressure-sensitive/chemical adhesives could be well avoided. Besides, the double-sided nanostructures showed great potential in finding new interesting properties and practical applications for the synthetic dry adhesives.

  10. Reverse energy pooling in a K-Na mixture

    Energy Technology Data Exchange (ETDEWEB)

    De Filippo, G.; Guldberg-Kjaer, S.; Milosevic, S.; Pedersen, J.O. [Niels Bohr Institute, O/rsted Laboratory, Universitetsparken 5, DK-2100 Copenhagen O/ (Denmark); Allegrini, M. [Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica, Universita di Pisa, Piazza Torricelli 2, I-56126, Pisa (Italy)]|[Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, Universita di Messina, Salita Sperone 31, I-98166, SantAgata-Messina (Italy)

    1998-01-01

    We report experimental rate coefficients for the reverse heteronuclear energy-pooling collisions K(5D)+Na(3S){r_arrow}K(4P)+Na(3P) and K(7S)+Na(3S){r_arrow}K(4P)+Na(3P) at thermal energies. Both reactions are exothermic and very high rates were observed showing that reverse exothermic energy-pooling is an order of magnitude more efficient than the corresponding forward endothermic energy-pooling reactions. This is in accordance with the general behavior of the exothermic and endothermic energy-pooling rate coefficients in alkali-metal atoms. In the experiment the potassium atoms were excited in two steps to either the 5D or 7S state via the 4P level using two broadband cw dye lasers. A double-modulation technique has been used to select the fluorescence contributions at the Na(3P{sub J}) exit channels due only to the above reactions. The ground-state sodium and potassium atom densities were measured by the absorption of lines from a K-Na hollow-cathode lamp. The measured densities and fluorescence intensities have been used to obtain absolute reverse energy-pooling rate coefficients. The contribution to the rate coefficients from other processes are discussed. {copyright} {ital 1998} {ital The American Physical Society}

  11. Reversible logic gate using adiabatic superconducting devices

    National Research Council Canada - National Science Library

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-01-01

    .... However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices...

  12. SELECTED PROBLEMS OF REVERSE LOGISTICS IN POLAND

    OpenAIRE

    Agata Mesjasz-Lech

    2009-01-01

    This paper presents the essence of reverse logistics and directions of physical and information flows between logistic network partners. It also analyses effects of implementation of the principles of reverse logistics in Poland in the years 2004-2007

  13. PREPARATION OF LAYERED DOUBLE HYDROXIDES

    National Research Council Canada - National Science Library

    OGAWA, MAKOTO; INOMATA, KAZUYA

    2011-01-01

    Layered double hydroxides (LDHs) are class of materials with useful properties associated with their anion exchange abilities for a wide range of applications including bio and environmental problems...

  14. Colored Flag by Double Refraction.

    Science.gov (United States)

    Reid, Bill

    1994-01-01

    Describes various demonstrations that illustrate double refraction and rotation of the plane of polarization in stressed, transparent plastics, with the consequent production of colored designs. (ZWH)

  15. Double-Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena

    Double-Skin Facades (DSF) are gaining popularity that, in fact, appears to be independent from sturdy critics of the concept in the past years. DSF buildings are being built in Europe and worldwide, DSF concept is being taught at schools of architecture and fully glazed office buildings are being...... favored by companies and their employees. To bring the reduction of energy use in these buildings application of suitable tools and methods is necessary to achieve successful design solutions. Earlier work on the topic of DSF modelling was examined from various publications. As a result, the main...... difficulties experienced by scientists when attempting to model DSF thermal and energy performance were examined. In addition, the lack of experimental studies and empirical validation of models was realized, many numerical models have not been empirically validated and most of them require an expert knowledge...

  16. Layered double hydroxides

    DEFF Research Database (Denmark)

    López Rayo, Sandra; Imran, Ahmad; Hansen, Hans Chr. Bruun

    2017-01-01

    A novel zinc (Zn) fertilizer concept based on Zn doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthetized, their chemical composition was analyzed and their nutrient release was studied in buffered solutions with different pH values. Uptake...... of Zn by barley (Hordeum vulgare cv. Antonia) was evaluated in short- (8 weeks), medium- (11 weeks) and long-term (28 weeks) experiments in quartz sand and in a calcareous soil enriched with Zn-doped Mg-Fe-LDHs. The Zn release rate of the Zn-doped Mg-Fe-LDHs was described by a first-order kinetics...

  17. Dual double field theory

    Energy Technology Data Exchange (ETDEWEB)

    Bergshoeff, Eric A. [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Hohm, Olaf [Simons Center for Geometry and Physics, Stony Brook University,Stony Brook, NY 11794-3636 (United States); Penas, Victor A. [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Riccioni, Fabio [INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy)

    2016-06-06

    We present the dual formulation of double field theory at the linearized level. This is a classically equivalent theory describing the duals of the dilaton, the Kalb-Ramond field and the graviton in a T-duality or O(D,D) covariant way. In agreement with previous proposals, the resulting theory encodes fields in mixed Young-tableau representations, combining them into an antisymmetric 4-tensor under O(D,D). In contrast to previous proposals, the theory also requires an antisymmetric 2-tensor and a singlet, which are not all pure gauge. The need for these additional fields is analogous to a similar phenomenon for “exotic' dualizations, and we clarify this by comparing with the dualizations of the component fields. We close with some speculative remarks on the significance of these observations for the full non-linear theory yet to be constructed.

  18. Coupled Double Quantum Wells

    Directory of Open Access Journals (Sweden)

    Élder Mantovani Lopes

    2010-12-01

    Full Text Available The progress of the semiconductor growth techniques allows the opportunity to produce new semiconductors devices that may contribute to the development of the nanotechnology. The fabrication of semiconductor heterostructures with high quality allows the obtaining of new effects based on the quantum properties of those systems, which have stimulated great technological interest, especially on the optoelectronic and telecommunications fields. In this work some basic concepts related to one of those heterostructures are discussed: the Coupled Double Quantum Well (CDQW. The deduction of the expression for the determination of the energy levels in CDQWs is presented in details. The results obtained through this expression are compared with experimental results obtained through photoluminescence (PL measurements, complementing the work.

  19. Reversible logic gate using adiabatic superconducting devices

    OpenAIRE

    Takeuchi, N.; Y. Yamanashi; Yoshikawa, N.

    2014-01-01

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic...

  20. Reverse Skyline Computation over Sliding Windows

    OpenAIRE

    Junchang Xin; Zhiqiong Wang; Mei Bai; Guoren Wang

    2015-01-01

    Reverse skyline queries have been used in many real-world applications such as business planning, market analysis, and environmental monitoring. In this paper, we investigated how to efficiently evaluate continuous reverse skyline queries over sliding windows. We first theoretically analyzed the inherent properties of reverse skyline on data streams and proposed a novel pruning technique to reduce the number of data points preserved for processing continuous reverse skyline queries. Then, an ...

  1. Magnetic reversals from planetary dynamo waves

    DEFF Research Database (Denmark)

    Sheyko, Andrey; Finlay, Chris; Jackson, Andrew

    2016-01-01

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes ...... to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals....

  2. Managing reverse exchanges in service supply chains

    OpenAIRE

    Kumar, V.; Amorim, M.; Bhattacharya, A; Garza, J.

    2016-01-01

    Purpose\\ud \\ud This study aims to address the management of reverse flows in the context of service supply chains. The study builds on the characteristics of services production reported in literature to: identify diverse types of reverse flows in services supply chains; discuss key issues associated to the management of reverse service flows; and suggest directions for research for developing the knowledge for management of reverse flows in service contexts.\\ud \\ud Design/Methodology/Approac...

  3. Draping Double-Layer Woven Fabrics Onto Double-Curvature ...

    African Journals Online (AJOL)

    Draping woven fabrics to complex parts with double curvature leads to complex redistribution and reorientation of the yarns in composites reinforced with woven preforms. To reduce the risk of fabric tearing or wrinkling we propose to use double-layer woven fabrics. This paper presents a simulation model for draping

  4. A 4 mm² Double Differential Torsional MEMS Accelerometer Based on a Double-Beam Configuration.

    Science.gov (United States)

    Miao, Tongqiao; Xiao, Dingbang; Li, Qingsong; Hou, Zhanqiang; Wu, Xuezhong

    2017-10-02

    This paper reports the design and simulation of a 4 mm² double differential torsional MEMS accelerometer based on a double-beam configuration. Based on the structure of conventional torsional accelerometers, normally composed of one pair of proof masses and one torsional beam, this work explores the double differential configuration: a torsional accelerometer with two pairs of unbalanced proof masses rotating in reverse. Also, the torsional beam is designed as a double-beam structure, which is a symmetrical structure formed by two torsional beams separated by a certain distance. The device area of the novel accelerometer is more than 50 times smaller than that of a traditional double differential torsional MEMS accelerometer. The FEM simulation results demonstrate that the smaller device does not sacrifice other specifications, such as mechanical sensitivity, nonlinearity and temperature robustness. The mechanical sensitivity and nonlinearity of a ±15 g measuring range is 59.4 fF/g and 0.88%, respectively. Compared with traditional single-beam silicon structures, the novel structure can achieve lower maximum principle stress in critical regions and reduce the possibility of failure when high-g acceleration loading is applied along all three axes. The mechanical noise equivalent acceleration is about 0.13 mg / Hz in the theoretical calculations and the offset temperature coefficient is 0.25 mg/ ℃ in the full temperature range of - 40 ℃ to 60 ℃ .

  5. Dynamic Reverse Code Generation for Backward Execution

    DEFF Research Database (Denmark)

    Lee, Jooyong

    2007-01-01

    . In this paper, we present a method to generate reverse code, so that backtracking can be performed by executing reverse code. The novelty of our work is that we generate reverse code on-the-fly, while running a debugger, which makes it possible to apply the method even to debugging multi-threaded programs....

  6. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Janusz K. Grabara; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  7. Prefix reversals on binary and ternary strings

    NARCIS (Netherlands)

    Hurkens, C.A.J.; van Iersel, L.J.J.; Keijsper, J.C.M.; Kelk, S.M.; Stougie, L.; Tromp, J.T.

    2007-01-01

    Given a permutation $\\pi$, the application of prefix reversal $f^{(i)}$ to $\\pi$ reverses the order of the first $i$ elements of $\\pi$. The problem of sorting by prefix reversals (also known as pancake flipping), made famous by Gates and Papadimitriou (Discrete Math., 27 (1979), pp. 47–57), asks

  8. Cleaning Our World through Reverse Graffiti

    Science.gov (United States)

    Randazzo, Gabe; LaJevic, Lisa

    2013-01-01

    Over the last decade artists have begun to experiment with "reverse pollution" techniques, such as reverse graffiti, which focuses on cleaning environmental surfaces. Having recently been introduced to the works of Moose, the artist known for inventing the reverse graffiti technique, the authors decided to design a curriculum to increase…

  9. Remote Whispering Applying Time Reversal

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-16

    The purpose of this project was to explore the use of time reversal technologies as a means for communication to a targeted individual or location. The idea is to have the privacy of whispering in one’s ear, but to do this remotely from loudspeakers not located near the target. Applications of this work include communicating with hostages and survivors in rescue operations, communicating imaging and operational conditions in deep drilling operations, monitoring storage of spent nuclear fuel in storage casks without wires, or clandestine activities requiring signaling between specific points. This technology provides a solution in any application where wires and radio communications are not possible or not desired. It also may be configured to self calibrate on a regular basis to adjust for changing conditions. These communications allow two people to converse with one another in real time, converse in an inaudible frequency range or medium (i.e. using ultrasonic frequencies and/or sending vibrations through a structure), or send information for a system to interpret (even allowing remote control of a system using sound). The time reversal process allows one to focus energy to a specific location in space and to send a clean transmission of a selected signal only to that location. In order for the time reversal process to work, a calibration signal must be obtained. This signal may be obtained experimentally using an impulsive sound, a known chirp signal, or other known signals. It may also be determined from a numerical model of a known environment in which the focusing is desired or from passive listening over time to ambient noise.

  10. How to play Reverse Hex

    DEFF Research Database (Denmark)

    Toft, Bjarne; Hayward, Ryan B.; Henderson, Philip

    2012-01-01

    We present new results on how to play Reverse Hex, also known as Rex, or Misère Hex, on n × n boards. We give new proofs – and strengthened versions – of Lagarias and Sleator’s theorem (for n × n boards, each player can prolong the game until the board is full, so the first/second player can always......, we find second-player winning replies. Finally, in response to comments by Martin Gardner, for each n ≤ 5, we give a simple winning strategy for the n × n board....

  11. Controversial reversal of nuclear option

    Directory of Open Access Journals (Sweden)

    Mesarović Miodrag

    2002-01-01

    Full Text Available Nuclear option is in a unique position to restore its original role of the main source of energy with an increased attention paid to the security of electricity supply as well as regulatory changes affecting fossil fuels, particularly with due introduction of climate change prevention measures. Recent developments indicate the advantages of nuclear option over other possible options in terms of sustainable development. However, a large number of controversial issues on nuclear energy make its reversal less clear. These are discussed with particular attention paid to recent developments worldwide, including the World Summit on Sustainable Development held in September 2002 in Johannesburg, South Africa.

  12. Presbycusis: reversible with anesthesia drugs?

    Science.gov (United States)

    Kocher, Carl A

    2009-02-01

    Age-related hearing impairment, or presbycusis, is a degenerative condition not currently treatable by medication. It is therefore significant that the author, as a patient, experienced a reversal of high-frequency hearing loss during a 2-day period following abdominal surgery with general anesthesia. This report documents the surgery and the subsequent restoration of hearing, which was bilateral and is estimated to have exceeded 50dB at 4kHz. A possible role is noted for anesthetic agents such as lidocaine, propofol, or fentanyl. This experience may hold a clue for research toward the development of medical treatments for presbycusis.

  13. Reversal of clonidine induced miosis by the alpha 2-adrenoreceptor antagonist RX 781094.

    OpenAIRE

    Clifford, J M; Day, M D; Orwin, J M

    1982-01-01

    Clonidine given i.v. at a dose of 0.1 mg and 0.2 mg was found to cause miosis in a placebo controlled double-blind study in six healthy volunteers. In a further single-blind placebo controlled study in three of these volunteers, the alpha 2-adrenoreceptor antagonist RX 781094 at a dose of 0.1 mg/kg i.v. reversed the miosis induced by i.v. clonidine 0.2 mg. At a dose of 0.05 mg/kg the miosis was partially reversed.

  14. Reversal of clonidine induced miosis by the alpha 2-adrenoreceptor antagonist RX 781094.

    Science.gov (United States)

    Clifford, J M; Day, M D; Orwin, J M

    1982-01-01

    Clonidine given i.v. at a dose of 0.1 mg and 0.2 mg was found to cause miosis in a placebo controlled double-blind study in six healthy volunteers. In a further single-blind placebo controlled study in three of these volunteers, the alpha 2-adrenoreceptor antagonist RX 781094 at a dose of 0.1 mg/kg i.v. reversed the miosis induced by i.v. clonidine 0.2 mg. At a dose of 0.05 mg/kg the miosis was partially reversed. PMID:6125202

  15. Investigations on double-diffused MOS transistors under ESD zap conditions

    NARCIS (Netherlands)

    Boselli, G.; Meeuwsen, Stan; Mouthaan, A.J.; Kuper, F.G.

    2001-01-01

    In this paper we analyzed, through experiments and 2-D simulations, the behavior under high reverse voltages of a double-diffused MOS transistor. It turned out that the drift diffusion region (resistor) between the drain contact and p-diffusion region (PI) plays an important role both in the

  16. Orbits of four double stars

    Directory of Open Access Journals (Sweden)

    Novaković B.

    2006-01-01

    Full Text Available We present orbits of four double stars. Orbits of stars WDS 23516+4205 = ADS 17050 and WDS 18239+5848 = ADS 11336 were calculated for the first time. Orbits of double stars WDS 02022+3643 = ADS 1613 and WDS 18443+3940 = ADS 11635 were revised. We have also determined their masses, dynamical parallaxes and ephemerides.

  17. Empirically Unbinding the Double Bind.

    Science.gov (United States)

    Olson, David H.

    The theoretical concept of the double bind and the possibilities for researching it are discussed. The author has observed that theory and research, which should be reciprocal and mutually beneficial, have been working, as concerns the double bind, at odds with one another. Two approaches to empirically investigating the concept are considered via…

  18. Hedging Double Barriers with Singles

    NARCIS (Netherlands)

    Sbuelz, A.

    2000-01-01

    Double barrier options provide risk managers with good-deal flexibility in tailoring portfolio returns.Their hedges offer full protection only if unwound along the barriers.This work provides non-dynamic hedges that project the risk of double barriers on to single barriers.Non-dynamic hedges

  19. Double layer relaxation in colloids

    NARCIS (Netherlands)

    Kijlstra, J.

    1992-01-01

    The purpose of the present study is to improve our insight into the relaxation of the electrical double layer around particles in hydrophobic sols. A detailed knowledge of the relaxation mechanisms is required to explain the behaviour of sols under conditions where the double layer is

  20. Double parton scattering theory overview

    NARCIS (Netherlands)

    Diehl, Markus; Gaunt, Jonathan R.

    2017-01-01

    The dynamics of double hard scattering in proton-proton collisions is quite involved compared with the familiar case of single hard scattering. In this contribution, we review our theoretical understanding of double hard scattering and of its interplay with other reaction mechanisms.

  1. Exercise prescription to reverse frailty.

    Science.gov (United States)

    Bray, Nick W; Smart, Rowan R; Jakobi, Jennifer M; Jones, Gareth R

    2016-10-01

    Frailty is a clinical geriatric syndrome caused by physiological deficits across multiple systems. These deficits make it challenging to sustain homeostasis required for the demands of everyday life. Exercise is likely the best therapy to reverse frailty status. Literature to date suggests that pre-frail older adults, those with 1-2 deficits on the Cardiovascular Health Study-Frailty Phenotype (CHS-frailty phenotype), should exercise 2-3 times a week, for 45-60 min. Aerobic, resistance, flexibility, and balance training components should be incorporated but resistance and balance activities should be emphasized. On the other hand, frail (CHS-frailty phenotype ≥ 3 physical deficits) older adults should exercise 3 times per week, for 30-45 min for each session with an emphasis on aerobic training. During aerobic, balance, and flexibility training, both frail and pre-frail older adults should work at an intensity equivalent to a rating of perceived exertion of 3-4 ("somewhat hard") on the Borg CR10 scale. Resistance-training intensity should be based on a percentage of 1-repetition estimated maximum (1RM). Program onset should occur at 55% of 1RM (endurance) and progress to higher intensities of 80% of 1RM (strength) to maximize functional gains. Exercise is the medicine to reverse or mitigate frailty, preserve quality of life, and restore independent functioning in older adults at risk of frailty.

  2. Silver nanoparticles immobilized onto polycaprolactone (PCL)/poly[2-(dimethylamino)ethyl metacrilate) nanofiber meshes; Imobilizacao de nanoparticulas de prata em malhas de nanofibras de poli(caprolactona)/poli[(2-dimetilamino)etil metacrilato

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Fernanda G.; Bonkovoski, Leticia C.; Witt, Maria A.; Rubira, Adley F.; Muniz, Edvani C. [Universidade Estadual de Maringa (GMPC/UEM), Maringa, PR (Brazil). Grupo de Materiais Polimericos e Compositos; Piai, Juliana F., E-mail: jupiai@yahoo.com.br [Universidade Estadual de Maringa (UEM), Umuarama, PR (Brazil)

    2015-07-01

    The present work comprises the fabrication of nanofiber meshes of polycaprolactone (PCL)/poly [(2-dimethylamino) ethyl methacrylate] (PDMAEMA) and the subsequent immobilization of silver nanoparticles, in order to obtain materials with potential application in tissue engineering. The nanofibers composed of different ratios of PDMAEMA / PCL (m/m) were obtained by electrospinning. These nanofiber meshes were then immersed in colloidal suspensions containing the AgNPs under different pH values to immobilize the nanoparticles onto the fiber's surface. A greater amount of AgNPs was deposited when the fibers were immersed in a solution of pH 5, as one can observe from the scanning electron microscopy (SEM) images and the X-ray spectroscopy (EDS) spectra. It was observed that the meshes of the blends suffered morphological changes after immersion in acid solution (pH 5), and, the deposition of AgNPs onto the meshes in general was more effective in acid environment (pH 5). (author)

  3. Modifications induced by swift heavy ions in poly(hydroxybutyrate-hydroxyvalerate) (PHB/HV) and poly({epsilon}-caprolactone) (PCL) films. Part 1. Thermal behaviour and molecular mass modifications

    Energy Technology Data Exchange (ETDEWEB)

    Rouxhet, L.; Legras, R. E-mail: legras@poly.ucl.ac.be

    2000-12-01

    Modifications induced by different energetic heavy ions in poly({epsilon}-caprolactone) (PCL) and poly(hydroxybutyrate-hydroxyvalerate) (PHB/HV) have been investigated by the differential scanning calorimetry (DSC) and steric exclusion chromatography (SEC). A certain dose of damages, depending mainly on the charge and mass of the ion and on the intensity of irradiation, has to be overcome in order to detect any effect on PHB/HV. Actually, at a given intensity of irradiation, superior to 10{sup 10} ions/cm{sup 2}, the level of damage intensity increased with the increase in charge and mass of the ion. Moreover, according to the SEC results, there seems to be a critical mass and/or charge threshold above which the dominant type of damages changes. As a matter of fact, high-density irradiation with Ar{sup 9+} and Kr{sup 15+} resulted mainly in chain scission whereas cross-linking was dominant when irradiating the polymer with Xe{sup 24+} and Pb{sup 56+}. The irradiation of PCL in the conditions studied did not modify significantly the values of the melting point, the crystallisation temperature and the molecular masses of the system studied. The main effect of the irradiation detected by the DSC is the cross-linking of the polymer chains.

  4. Natural double inflation

    Science.gov (United States)

    Occhionero, F.; Litterio, M.; Capozziello, S.; Amendola, L.

    The astronomical interest of double inflation stems from the possibility it gives of inserting a feature in an otherwise featureless (or scale invariant) perturbation spectrum, precisely at the scale (100 Mpc, say) that goes through the horizon at the (sharp) separations between the two successive inflations. Double inflation occurs when two scalar fields (or inflatons) dominate sequentially the cosmic expansion or when vacuum polarization — Ricci scalar R squared added to the Lagrangian — is taken into account and only one inflaton ψ is present. (This perhaps is more natural as it exploits quantum effects to reduce to one the number of the ad hoc ingredients.) In that case we know from Starobinsky's pioneering work that the first inflation is driven by R — rightly called then scalaron — under the rules of Fourth Order Gravity, (FOG), while the second is driven by ψ under the rules of ordinary General Relativity, (GR). Unfortunately most of the appeal of the scalaron-inflaton scenario in relation to the feature in the perturbation spectrum, is lost because a delicate fine tuning of the value of the (second) inflaton at the beginning of the second inflation is required, in the absence of which the two inflations merge in one and no scale is singled out. In order to overcome this difficulty, we introduce in the Lagrangian density a new scalar coupling between ψ and R2, analogous to the well known non minimal coupling between ψ and R of canonical GR. We show that in this way the two inflationary episodes of FOG and GR may be neatly distinguished from each other, regardless of the initial value of ψ. This is due to the influence of the coupling on the shape of the conformal potential, in which one can easily carve a channel of evolution, consisting in fact of two orthogonal valleys. Then, for most of phase space the attractor is this doubly inflationary trajectory that lies at the bottom of the two valleys (Fig. 1). In fact, in this case the Universe first

  5. Reverse Skyline Computation over Sliding Windows

    Directory of Open Access Journals (Sweden)

    Junchang Xin

    2015-01-01

    Full Text Available Reverse skyline queries have been used in many real-world applications such as business planning, market analysis, and environmental monitoring. In this paper, we investigated how to efficiently evaluate continuous reverse skyline queries over sliding windows. We first theoretically analyzed the inherent properties of reverse skyline on data streams and proposed a novel pruning technique to reduce the number of data points preserved for processing continuous reverse skyline queries. Then, an efficient approach, called Semidominance Based Reverse Skyline (SDRS, was proposed to process continuous reverse skyline queries. Moreover, an extension was also proposed to handle n-of-N and (n1,n2-of-N reverse skyline queries. Our extensive experimental studies have demonstrated the efficiency as well as effectiveness of the proposed approach with various experimental settings.

  6. A Handbook of Double Stars

    Science.gov (United States)

    Crossley, Edward; Gledhill, Joseph; Wilson, James M.

    2011-11-01

    Preface; Part I. Historical, and Descriptive of Instruments and Methods: 1. Historical introduction; 2. The Equatorial: its construction and adjustments; 3. Some account of the Equatorials which have been used by double-star observers; 4. The micrometer; 5. Methods of observing double stars; Part II. On the Calculation of the Orbit of a Binary Star: 1. Introduction; 2. Example of an orbit worked by a graphical method; 3. Dr. Doberck's example of an orbit worked by analytical methods; 4. On relative rectilinear motion; 5. On the effect of proper motion and parallax on the observed position angles and distance of an optically double star; 6. On the errors of observation and the combination of observations; Part III. The Catalogue and Measures: Introductory remarks; A catalogue of binary and other double starts deserving of attention; Lists of measures, with historical notes, etc.; Supplementary list of measures; Appendix; Additional notes to measures; Binary stars classified; Note on systematic errors in the measures of angle and distance of double stars; Part IV. Bibliography: A. Some of the most important works and papers on double stars; B. Some papers on the micrometer; C. Some papers on the colours of double stars; Additional notes; Corrections 1880.

  7. Reversibly assembled cellular composite materials.

    Science.gov (United States)

    Cheung, Kenneth C; Gershenfeld, Neil

    2013-09-13

    We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing.

  8. Reverse Flow Pressure Limiting Aperture.

    Science.gov (United States)

    Danilatos

    2000-01-01

    The reverse flow pressure limiting aperture is a device that creates and sustains a substantial gas pressure difference between two chambers connected via an aperture. The aperture is surrounded by an annular orifice leading to a third chamber. The third chamber is maintained at a relatively high pressure that forces gas to flow through the annular aperture into the first of said two chambers. The ensuing gas flow develops into a supersonic annular gas jet, the core of which is coaxial with the central aperture. A pumping action is created at the core of the jet and any gas molecules leaking through the aperture from the second chamber are entrained and forced into the first chamber, thus creating a substantial pressure difference between the first and second chamber.

  9. Creative Double Bind in Oral Interpretation.

    Science.gov (United States)

    Peterson, Eric E.; Langellier, Kristin M.

    1982-01-01

    Explains how oral interpretation is uniquely communicative and how the double bind theory of communication can include creativity. Discusses (1) double bind and oral interpretation, (2) creating aesthetic text, and (3) the performance of double bind. (PD)

  10. Reverse breeding: a novel breeding approach based on engineered meiosis

    Science.gov (United States)

    Dirks, Rob; van Dun, Kees; de Snoo, C Bastiaan; van den Berg, Mark; Lelivelt, Cilia L C; Voermans, William; Woudenberg, Leo; de Wit, Jack P C; Reinink, Kees; Schut, Johan W; van der Zeeuw, Eveline; Vogelaar, Aat; Freymark, Gerald; Gutteling, Evert W; Keppel, Marina N; van Drongelen, Paul; Kieny, Matthieu; Ellul, Philippe; Touraev, Alisher; Ma, Hong; de Jong, Hans; Wijnker, Erik

    2009-01-01

    Reverse breeding (RB) is a novel plant breeding technique designed to directly produce parental lines for any heterozygous plant, one of the most sought after goals in plant breeding. RB generates perfectly complementing homozygous parental lines through engineered meiosis. The method is based on reducing genetic recombination in the selected heterozygote by eliminating meiotic crossing over. Male or female spores obtained from such plants contain combinations of non-recombinant parental chromosomes which can be cultured in vitro to generate homozygous doubled haploid plants (DHs). From these DHs, complementary parents can be selected and used to reconstitute the heterozygote in perpetuity. Since the fixation of unknown heterozygous genotypes is impossible in traditional plant breeding, RB could fundamentally change future plant breeding. In this review, we discuss various other applications of RB, including breeding per chromosome. PMID:19811618

  11. Reversible patterning of spherical shells through constrained buckling

    Science.gov (United States)

    Marthelot, J.; Brun, P.-T.; Jiménez, F. López; Reis, P. M.

    2017-07-01

    Recent advances in active soft structures envision the large deformations resulting from mechanical instabilities as routes for functional shape morphing. Numerous such examples exist for filamentary and plate systems. However, examples with double-curved shells are rarer, with progress hampered by challenges in fabrication and the complexities involved in analyzing their underlying geometrical nonlinearities. We show that on-demand patterning of hemispherical shells can be achieved through constrained buckling. Their postbuckling response is stabilized by an inner rigid mandrel. Through a combination of experiments, simulations, and scaling analyses, our investigation focuses on the nucleation and evolution of the buckling patterns into a reticulated network of sharp ridges. The geometry of the system, namely, the shell radius and the gap between the shell and the mandrel, is found to be the primary ingredient to set the surface morphology. This prominence of geometry suggests a robust, scalable, and tunable mechanism for reversible shape morphing of elastic shells.

  12. Principles of a reversible programming language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    features of the language include explicit post-condition assertions, direct access to an inverse semantics and the possibility of clean (i.e., garbage-free) computation of injective functions. We suggest the clean simulation of reversible Turing machines as a criterion for computing strength of reversible......The principles of reversible programming languages are explicated and illustrated with reference to the design of a high-level imperative language, Janus. The fundamental properties for such languages include backward as well as forward determinism and reversible updates of data. The unique design...... languages, and demonstrate this for Janus. We show the practicality of the language by implementation of a reversible fast Fourier transform. Our results indicate that the reversible programming paradigm has fundamental properties that are relevant to many different areas of computer science....

  13. Reversing cell polarity: evidence and hypothesis.

    Science.gov (United States)

    Kaiser, Dale; Yu, Rosa

    2005-04-01

    The long, rod-shaped cells of myxobacteria are polarized by their gliding engines. At the rear, A-engines push while pili pull the front end forward. An hypothesis is developed whereby both engines are partially dis-assembled, then re-assembled at the opposite pole when cells reverse their movement direction. Reversals are induced by an Mgl G-protein switch that controls engine polarity. The switch is driven by an oscillatory circuit of Frizzy proteins. In growing cells, the circuit gives rise to an occasional reversal that makes swarming possible. Then, as myxobacteria begin fruiting body development, a rising level of C-signal input drives the oscillator and changes the reversal pattern. Cells reverse regularly every eight minutes in traveling waves, the reversal period is then prolonged enabling cells to form streams that enlarge tiny random aggregates into fruiting bodies.

  14. Isotropy equilibrium of the double woven fabric with cotton face and wool reverse fibrous compositions

    Science.gov (United States)

    Rahnev, I.; Rimini, G.

    2017-10-01

    The equilibrium of the masses and the mechanical properties between the warp and the weft is a determining factor for the quality of the woven fabrics. When the fabric has a multi-layered structure and is designed for protective clothing, the uniform distribution of the elastical resistance acquires a paramount importance for the consumer properties. Isotropy in the sense of absolute equalising of the properties between the base and the weft evaluates the achieved optimum cohesion between the weaving threads and directs the weaving cycle settings. The possible variation of the ratio between the elastic modules of the warp and the weft, depending on the weft spacing and the warp tension, is the basic idea of this article.

  15. Gravity controlled anti-reverse rotation device

    Science.gov (United States)

    Dickinson, Robert J.; Wetherill, Todd M.

    1983-01-01

    A gravity assisted anti-reverse rotation device for preventing reverse rotation of pumps and the like. A horizontally mounted pawl is disposed to mesh with a fixed ratchet preventing reverse rotation when the pawl is advanced into intercourse with the ratchet by a vertically mounted lever having a lumped mass. Gravitation action on the lumped mass urges the pawl into mesh with the ratchet, while centrifugal force on the lumped mass during forward, allowed rotation retracts the pawl away from the ratchet.

  16. Reverse-symmetry waveguides: Theory and fabrication

    DEFF Research Database (Denmark)

    Horvath, R.; Lindvold, Lars René; Larsen, N.B.

    2002-01-01

    We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractiv...... has the advantage of deeper penetration of the evanescent electromagnetic field into the cover medium, theoretically permitting higher sensitivity to analytes compared to traditional waveguide designs. We present calculated sensitivities and probing depths of conventional and reverse...

  17. Reverse Logistics - a review of case studies

    OpenAIRE

    Brito, Marisa; Dekker, Rommert; Flapper, S.D.P.

    2003-01-01

    textabstractProducts, components, materials and other equipment stream forward and back wards and back in their supply chains. Reverse Logistics deals with the processes associated with the reverse stream from users/owners to re-users. This paper provides a review and content analysis of scientific literature on reverse logistics case studies. Over sixty case studies are included. In addition, we give an overview of particular issues, which we link with propositions, unanswered questions and ...

  18. REVERSE LOGISTICS AND APPLICATION OF ARAS METHOD

    OpenAIRE

    Koc, Nesrin; Uysal, Fahriye

    2017-01-01

    Purpose-In recent years, product recovery, environmental awareness, efficient use ofresources and sustainability issues have gained importance. For this reason,the importance attached to reverse logistics activities of information andproducts towards the starting point of the final user is also increasing.Reverse logistics gives firms a competitive advantage and allows them to createan image of an environmentalist firm. In this context, the critical successfactors that influence reverse logis...

  19. Hitchcock’s queer doubles

    Directory of Open Access Journals (Sweden)

    Alessandra Brandão

    2013-12-01

    Full Text Available http://dx.doi.org/10.5007/2175-8026.2013n65p17   The “double” is a well-known Hitchcockian motif. Widelyreviewed under a psychoanalytical perspective, the issue ofthe double still presents other important challenges and thisarticle aims at discussing the queer doubles in Hitchcock’s films as “falsifiers” who are opposed to non-queer doubles thatemphasise narrative coherence and legibility. In films such asRebeca, Rope, Vertigo, The Birds, Psycho, and Frenzy, a doublecondenses impulses that are well described by Lee Edelman: “theviolent undoing of meaning, the loss of identity and coherence,the unnatural access to jouissance” (132. These doubles releasethe powers of the false as they complicate the return to an “order”.Therefore, we could argue that such characters are closer tobeing Deleuzian simulacra than psychoanalytical doppelgängers.

  20. Species doubling and effective Lagrangians

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, M.; Tytgat, M.

    1996-09-01

    Coupling gauge fields to the chiral currents from an effective Lagrangian for pseudoscalar mesons naturally gives rise to a species doubling phenomenon similar to that seen with fermionic fields in lattice gauge theory. 17 refs.

  1. The Double Love Commandment

    Directory of Open Access Journals (Sweden)

    Francois P. Viljoen

    2015-03-01

    Full Text Available The Gospel of Matthew was written during a period of dispute between the Matthean community and their fellow Jews, with the Pharisees playing a leading role. The Matthean community was heir to the same scriptures as its opponents. They continued to have a firm commitment to the Torah, but they developed a distinctive understanding of it based on Jesus’ teaching. The formation of this community is investigated in this article, considering the Mediterranean perspectives of group-oriented societies prevalent in the first century. Such a group provided a sense of self and an interactive support system, where love functioned to bind the group together. The subordinates showed their undivided loyalty towards their superiors because of the favours they received from them, whilst they supported and cared for other members within the group as they care for themselves. Reading the double love commandment of Matthew 22:34−40 from this perspective reveals significant aspects of the community’s identity with regard to their commitment to God and their view of their neighbours. Die Dubbele Liefdesgebod. Die Matteusevangelie is gedurende ’n periode van konfliktussen die Matteusgemeenskap en mede-Jode geskryf met die Fariseërs in ’n leidende rol. Die Matteusgemeenskap het van dieselfde geskrifte as hulle opponente gebruik gemaak. Hulle was steeds aan die Torah lojaal, maar het ’n unieke interpretasie daarvan gehuldig, gebaseer op die onderrig van Jesus. In hierdie artikel word die vorming van die Matteusgemeenskap ondersoek met inagneming van die Mediterreense beskouing van die groepgeoriënteerde gemeenskappe wat tipies van die eerste eeu was. So ’n groep het aan individue ’n bewustheid van eie waarde verskaf te midde van ’n interaktiewe ondersteuningsisteem waarin liefde as samebindende faktor gefunksioneer het. Ondergeskiktes het onverdeelde lojaliteit teenoor hulle meerderes betoon vanweë die gunste wat hulle van die meerderes geniet het

  2. The Double Love Commandment

    Directory of Open Access Journals (Sweden)

    Francois P. Viljoen

    2015-03-01

    Full Text Available The Gospel of Matthew was written during a period of dispute between the Matthean community and their fellow Jews, with the Pharisees playing a leading role. The Matthean community was heir to the same scriptures as its opponents. They continued to have a firm commitment to the Torah, but they developed a distinctive understanding of it based on Jesus’ teaching. The formation of this community is investigated in this article, considering the Mediterranean perspectives of group-oriented societies prevalent in the first century. Such a group provided a sense of self and an interactive support system, where love functioned to bind the group together. The subordinates showed their undivided loyalty towards their superiors because of the favours they received from them, whilst they supported and cared for other members within the group as they care for themselves. Reading the double love commandment of Matthew 22:34−40 from this perspective reveals significant aspects of the community’s identity with regard to their commitment to God and their view of their neighbours.Die Dubbele Liefdesgebod. Die Matteusevangelie is gedurende ’n periode van konfliktussen die Matteusgemeenskap en mede-Jode geskryf met die Fariseërs in ’n leidende rol. Die Matteusgemeenskap het van dieselfde geskrifte as hulle opponente gebruik gemaak. Hulle was steeds aan die Torah lojaal, maar het ’n unieke interpretasie daarvan gehuldig, gebaseer op die onderrig van Jesus. In hierdie artikel word die vorming van die Matteusgemeenskap ondersoek met inagneming van die Mediterreense beskouing van die groepgeoriënteerde gemeenskappe wat tipies van die eerste eeu was. So ’n groep het aan individue ’n bewustheid van eie waarde verskaf te midde van ’n interaktiewe ondersteuningsisteem waarin liefde as samebindende faktor gefunksioneer het. Ondergeskiktes het onverdeelde lojaliteit teenoor hulle meerderes betoon vanweë die gunste wat hulle van die meerderes geniet het

  3. Inappropriate Use of the Quasi-Reversible Electrode Kinetic Model in Simulation-Experiment Comparisons of Voltammetric Processes That Approach the Reversible Limit

    KAUST Repository

    Simonov, Alexandr N.

    2014-08-19

    Many electrode processes that approach the "reversible" (infinitely fast) limit under voltammetric conditions have been inappropriately analyzed by comparison of experimental data and theory derived from the "quasi-reversible" model. Simulations based on "reversible" and "quasi-reversible" models have been fitted to an extensive series of a.c. voltammetric experiments undertaken at macrodisk glassy carbon (GC) electrodes for oxidation of ferrocene (Fc0/+) in CH3CN (0.10 M (n-Bu)4NPF6) and reduction of [Ru(NH 3)6]3+ and [Fe(CN)6]3- in 1 M KCl aqueous electrolyte. The confidence with which parameters such as standard formal potential (E0), heterogeneous electron transfer rate constant at E0 (k0), charge transfer coefficient (α), uncompensated resistance (Ru), and double layer capacitance (CDL) can be reported using the "quasi- reversible" model has been assessed using bootstrapping and parameter sweep (contour plot) techniques. Underparameterization, such as that which occurs when modeling CDL with a potential independent value, results in a less than optimal level of experiment-theory agreement. Overparameterization may improve the agreement but easily results in generation of physically meaningful but incorrect values of the recovered parameters, as is the case with the very fast Fc0/+ and [Ru(NH3)6]3+/2+ processes. In summary, for fast electrode kinetics approaching the "reversible" limit, it is recommended that the "reversible" model be used for theory-experiment comparisons with only E0, R u, and CDL being quantified and a lower limit of k 0 being reported; e.g., k0 ≥ 9 cm s-1 for the Fc0/+ process. © 2014 American Chemical Society.

  4. Keepers of the Double Stars

    OpenAIRE

    Tenn, Joseph S.

    2013-01-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Early catalogues by the Herschels, Struves, and others began with their own discoveries. In 1906 court reporter and amateur astronomer Sherburne Wesley Burnham published a massive double star catalogue containing data from many observers on more than 13,000 systems. Lick Observatory astronomer Robert Grant Aitken produced a much larger catalogue in 19...

  5. Double parton scattering in CMS

    CERN Document Server

    Sunar Cerci, Deniz

    2017-01-01

    Recent results on the double parton scattering measurements performed using the proton-proton collision data collected with the CMS detector are presented. The observables, which are sensitive to double parton scattering, are investigated after being corrected for detector effects and selection efficiencies. Multivariate analysis techniques are used for increasing the sensitivity. The effective cross section, $\\sigma_{eff}$ is also extracted using different processes at various center-of-mass energies.

  6. Supermagic Generalized Double Graphs 1

    Directory of Open Access Journals (Sweden)

    Ivančo Jaroslav

    2016-02-01

    Full Text Available A graph G is called supermagic if it admits a labelling of the edges by pairwise di erent consecutive integers such that the sum of the labels of the edges incident with a vertex is independent of the particular vertex. In this paper we will introduce some constructions of supermagic labellings of some graphs generalizing double graphs. Inter alia we show that the double graphs of regular Hamiltonian graphs and some circulant graphs are supermagic.

  7. Combining or Separating Forward and Reverse Logistics

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel; Nielsen, Anders

    2017-01-01

    Purpose – While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine reverse logistics with forward logistics, keep the flows separated, or choose......-research addresses intra-RL issues while the relationship between forward and reverse logistics is under-researched. This paper contributes to RL-theory by identifying the contextual factors that determine the most advantageous relationship between forward and reverse logistics, and proposes a novel decision making...

  8. Parallelization of Reversible Ripple-carry Adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2009-01-01

    {O}(m\\cdot k)$. The underlying mechanisms of the parallelization scheme are formally proven correct. We also show designs for garbage-less reversible comparison circuits. We compare the circuit costs of the resulting ripple-block carry adder with known optimized reversible ripple-carry adders in measures...... wherein $m$ parallel $k$-bit reversible ripple-carry adders are combined to form a reversible $mk$-bit \\emph{ripple-block carry adder} with logic depth $\\mathcal{O}(m+k)$ for a \\emph{minimal} logic depth $\\mathcal{O}(\\sqrt{mk})$, thus improving on the $mk$-bit ripple-carry adder logic depth $\\mathcal...

  9. Fabrication and characterization of SrAl{sub 2}O{sub 4}: Eu{sup 2+} Dy{sup 3+}/CS-PCL electrospun nanocomposite scaffold for retinal tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Sepahvandi, Azadeh; Eskandari, Mahnaz, E-mail: eskandarim@aut.ac.ir; Moztarzadeh, Fathollah

    2016-09-01

    Millions of people around the world become blind due to losing a part of the retina cells. In tissue engineering field one way to address this issue is to develop a retina tissue by scaffolds based on structure and signals received These scaffolds can play an essential role in repair and reformation of the damaged retina tissue. Here, SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+} nanophosphor were prepared by sol-gel method and then coated with PEG to become biocompatible. Next 10%, 30% and 50% concentration of the coated nanophosphors were dispersed in CS-PCL copolymer and electrospuned to form SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+}/CS-PCL scaffolds. The aforementioned photo –luminescence-scaffolds were studied for their optical, mechanical and morphological characteristics finally the effect of these scaffolds on the mice RPCs cells' proliferation and differentiation was observed. The 30% nanophosphor dispersion scaffold while providing adequate mechanical flexibility and integrity, and exhibiting superior proliferation rates and acceptable differentiation into retinal neural cells (particularly photo receptors retinal) is suggested as a promising choice in retinal tissue repair. - Highlights: • The 30% nanophosphor dispersion scaffold for both shorter wavelength and middle intense emission is more near to biocompatible nanophosphors. • 30% dispersed nanophosphor scaffold displays satisfactory mechanical strength and flexibility where its behavior is similar to the retina tissue. • Besides as the most effective signal in this study is the electromagnetic signals emitted by nanophosphors, we attribute the enhanced proliferation to the positive effects of the later, the emitted signals of scaffolds. • The tendency towards spherical morphology implies that emitting light may stimulate the cell signaling toward differentiation • These findings implies that mRPC grown on SrAl{sub 2}O{sub 4}: Eu{sup 2+},Dy{sup 3+}/CS-PCL scaffolds in differentiation

  10. [Intra-articular reinforcement of a partially torn anterior cruciate ligament (ACL) using newly developed UHMWPE biomaterial in combination with Hexalon ACL/PCL screws: ex-vivo mechanical testing of an animal knee model].

    Science.gov (United States)

    Fedorová, P; Srnec, R; Pěnčík, J; Dvořák, M; Krbec, M; Nečas, A

    2015-01-01

    PURPOSE OF THE STUDY Recent trends in the experimental surgical management of a partial anterior cruciate ligament (ACL) rupture in animals show repair of an ACL lesion using novel biomaterials both for biomechanical reinforcement of a partially unstable knee and as suitable scaffolds for bone marrow stem cell therapy in a partial ACL tear. The study deals with mechanical testing of the newly developed ultra-high-molecular-weight polyethylene (UHMWPE) biomaterial anchored to bone with Hexalon biodegradable ACL/PCL screws, as a new possibility of intra-articular reinforcement of a partial ACL tear. MATERIAL AND METHODS Two groups of ex vivo pig knee models were prepared and tested as follows: the model of an ACL tear stabilised with UHMWPE biomaterial using a Hexalon ACL/PCL screw (group 1; n = 10) and the model of an ACL tear stabilised with the traditional, and in veterinary medicine used, extracapsular technique involving a monofilament nylon fibre, a clamp and a Securos bone anchor (group 2; n = 11). The models were loaded at a standing angle of 100° and the maximum load (N) and shift (mm) values were recorded. RESULTS In group 1 the average maximal peak force was 167.6 ± 21.7 N and the shift was on average 19.0 ± 4.0 mm. In all 10 specimens, the maximum load made the UHMWPE implant break close to its fixation to the femur but the construct/fixation never failed at the site where the material was anchored to the bone. In group 2, the average maximal peak force was 207.3 ± 49.2 N and the shift was on average 24.1 ± 9.5 mm. The Securos stabilisation failed by pullout of the anchor from the femoral bone in nine out of 11 cases; the monofilament fibre ruptured in two cases. CONCLUSIONS It can be concluded that a UHMWPE substitute used in ex-vivo pig knee models has mechanical properties comparable with clinically used extracapsular Securos stabilisation and, because of its potential to carry stem cells and bioactive substances, it can meet the requirements for

  11. Reverse ethnopharmacology and drug discovery.

    Science.gov (United States)

    Leonti, Marco; Stafford, Gary I; Cero, Maja Dal; Cabras, Stefano; Castellanos, Maria Eugenia; Casu, Laura; Weckerle, Caroline S

    2017-02-23

    Ethnopharmacological investigations of traditional medicines have made significant contributions to plant-derived drugs, as well as the advancement of pharmacology. Drug discovery from medicinal flora is more complex than generally acknowledged because plants are applied for different therapeutic indications within and across cultures. Therefore we propose the concept of "reverse ethnopharmacology" and compare biomedical uses of plant taxa with their ethnomedicinal and popular uses and test the effect of these on the probability of finding biomedical and specifically anticancer drugs. For this analysis we use data on taxonomy and medical indications of plant derived biomedical drugs, clinical trial, and preclinical trial drug candidates published by Zhu et al. (2011) and compare their therapeutic indications with their ethnomedicinal and popular uses as reported in the NAPRALERT® database. Specifically, we test for increase or decrease of the probability of finding anticancer drugs based on ethnomedicinal and popular reports with Bayesian logistic regression analyses. Anticancer therapy resulted as the most frequent biomedicinal indication of the therapeutics derived from the 225 drug producing higher plant taxa and showed an association with ethnomedicinal and popular uses in women's medicine, which was also the most important popular use-category. Popular remedies for dysmenorrhoea, and uses as emmenagogues, abortifacients and contraceptives showed a positive effect on the probability of finding anticancer drugs. Another positive effect on the probability of discovering anticancer therapeutics was estimated for popular herbal drugs associated with the therapy of viral and bacterial infections, while the highest effect was found for popular remedies used to treat cancer symptoms. However, this latter effect seems to be influenced by the feedback loop and divulgence of biomedical knowledge on the popular level. We introduce the concept of reverse ethnopharmacology

  12. Reverse Engineering Adverse Outcome Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, Edward; Chipman, J.K.; Edwards, Stephen; Habib, Tanwir; Falciani, Francesco; Taylor, Ronald C.; Van Aggelen, Graham; Vulpe, Chris; Antczak, Philipp; Loguinov, Alexandre

    2011-01-30

    The toxicological effects of many stressors are mediated through unknown, or poorly characterized, mechanisms of action. We describe the application of reverse engineering complex interaction networks from high dimensional omics data (gene, protein, metabolic, signaling) to characterize adverse outcome pathways (AOPs) for chemicals that disrupt the hypothalamus-pituitary-gonadal endocrine axis in fathead minnows. Gene expression changes in fathead minnow ovaries in response to 7 different chemicals, over different times, doses, and in vivo versus in vitro conditions were captured in a large data set of 868 arrays. We examined potential AOPs of the antiandrogen flutamide using two mutual information theory methods, ARACNE and CLR to infer gene regulatory networks and potential adverse outcome pathways. Representative networks from these studies were used to predict a network path from stressor to adverse outcome as a candidate AOP. The relationship of individual chemicals to an adverse outcome can be determined by following perturbations through the network in response to chemical treatment leading to the nodes associated with the adverse outcome. Identification of candidate pathways allows for formation of testable hypotheses about key biologic processes, biomarkers or alternative endpoints, which could be used to monitor an adverse outcome pathway. Finally, we identify the unique challenges facing the application of this approach in ecotoxicology, and attempt to provide a road map for the utilization of these tools. Key Words: mechanism of action, toxicology, microarray, network inference

  13. Reverse genetics in ecological research.

    Directory of Open Access Journals (Sweden)

    Jens Schwachtje

    Full Text Available By precisely manipulating the expression of individual genetic elements thought to be important for ecological performance, reverse genetics has the potential to revolutionize plant ecology. However, untested concerns about possible side-effects of the transformation technique, caused by Agrobacterium infection and tissue culture, on plant performance have stymied research by requiring onerous sample sizes. We compare 5 independently transformed Nicotiana attenuata lines harboring empty vector control (EVC T-DNA lacking silencing information with isogenic wild types (WT, and measured a battery of ecologically relevant traits, known to be important in plant-herbivore interactions: phytohormones, secondary metabolites, growth and fitness parameters under stringent competitive conditions, and transcriptional regulation with microarrays. As a positive control, we included a line silenced in trypsin proteinase inhibitor gene (TPI expression, a potent anti-herbivore defense known to exact fitness costs in its expression, in the analysis. The experiment was conducted twice, with 10 and 20 biological replicates per genotype. For all parameters, we detected no difference between any EVC and WT lines, but could readily detect a fitness benefit of silencing TPI production. A statistical power analyses revealed that the minimum sample sizes required for detecting significant fitness differences between EVC and WT was 2-3 orders of magnitude larger than the 10 replicates required to detect a fitness effect of TPI silencing. We conclude that possible side-effects of transformation are far too low to obfuscate the study of ecologically relevant phenotypes.

  14. Reversible hypothyroidism and Whipple's disease

    Directory of Open Access Journals (Sweden)

    Tran Huy A

    2006-05-01

    Full Text Available Abstract Background The major cause of primary hypothyroidism is autoimmune mediated with progressive and permanent destruction of the thyroid gland resulting in life-long replacement therapy. Treatable and reversible hypothyroidism is unusual and here forth is such a case due to infection of the thyroid gland with Tropheryma whippleii, Whipple disease. Case presentation A 45 year-old female presented with symptoms and signs consistent with primary hypothyroidism, which was also confirmed biochemically. Her response to thyroxine replacement therapy was poor however, requiring a significantly elevated amount. Further investigation revealed the presence of Whipple's disease involving the gastrointestinal trace and possibly the thyroid gland. Her thyroxine requirement decreased drastically following appropriate antimicrobial therapy for Whipple's disease to the extent that it was ceased. Thyrotropin releasing hormone testing in the steady state suggested there was diminished thyroid reserve due to Whipple's disease. Conclusion This is the first ante-mortem case report studying the possible involvement of the thyroid gland by Whipple's disease. Despite the normalization of her thyroid function test biochemically after antibiotic therapy, there is diminished thyroid reserve thus requiring close and regular monitoring.

  15. Methylthioadenosine reverses brain autoimmune disease.

    Science.gov (United States)

    Moreno, Beatriz; Hevia, Henar; Santamaria, Monica; Sepulcre, Jorge; Muñoz, Javier; García-Trevijano, Elena R; Berasain, Carmen; Corrales, Fernando J; Avila, Matias A; Villoslada, Pablo

    2006-09-01

    To assess the immunomodulatory activity of methylthioadenosine (MTA) in rodent experimental autoimmune encephalomyelitis (EAE) and in patients with multiple sclerosis. We studied the effect of intraperitoneal MTA in the acute and chronic EAE model by quantifying clinical and histological scores and by performing immunohistochemistry stains of the brain. We studied the immunomodulatory effect of MTA in lymphocytes from EAE animals and in peripheral blood mononuclear cells from healthy control subjects and multiple sclerosis patients by assessing cell proliferation and cytokine gene expression, by real-time polymerase chain reaction, and by nuclear factor-kappaB modulation by Western blot. We found that MTA prevents acute EAE and, more importantly, reverses chronic-relapsing EAE. MTA treatment markedly inhibited brain inflammation and reduced brain damage. Administration of MTA suppressed T-cell activation in vivo and in vitro, likely through a blockade in T-cell signaling resulting in the prevention of inhibitor of kappa B (IkappaB-alpha) degradation and in the impaired activation transcription factor nuclear factor-kappaB. Indeed, MTA suppressed the production of proinflammatory genes and cytokines (interferon-gamma, tumor necrosis factor-alpha, and inducible nitric oxide synthase) and increased the production of antiinflammatory cytokines (interleukin-10). MTA has a remarkable immunomodulatory activity and may be beneficial for multiple sclerosis and other autoimmune diseases.

  16. Reversed shunting in CREST syndrome.

    Science.gov (United States)

    Kafes, Habibe; Sen, Fatih; Unal, Sefa; Acar, Burak; Ozeke, Ozcan

    2016-07-08

    The patent foramen ovale (PFO) is one of the most common congenital defects and may as well stand for "potential for opening" in addition to patent foramen ovale. Although patients are usually asymptomatic because the defect is flap-like and does not permit significant left-to-right shunting, the pathological conditions that result in cardiac rotation or higher than normal right atrial pressures can reverse the normal left atrial to right atrial pressure gradient and cause a right-to-left shunt through a PFO. Pulmonary complications of systemic sclerosis (SSc) are common, and are the leading cause of SSc-related death. The most common pulmonary manifestations of SSc are pulmonary hypertension (PAH), interstitial lung disease, and any combination thereof. Compared with the idiopathic form of PAH (IPAH), patients with SSc-associated PAH have a threefold increased risk of death and may receive a diagnosis late in the course of disease because of insidious onset and the high prevalence of cardiac, musculoskeletal, and pulmonary parenchymal comorbidities. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 44:390-391, 2016. © 2015 Wiley Periodicals, Inc.

  17. Modular microfluidic systems using reversibly attached PDMS fluid control modules

    Science.gov (United States)

    Skafte-Pedersen, Peder; Sip, Christopher G.; Folch, Albert; Dufva, Martin

    2013-05-01

    The use of soft lithography-based poly(dimethylsiloxane) (PDMS) valve systems is the dominating approach for high-density microscale fluidic control. Integrated systems enable complex flow control and large-scale integration, but lack modularity. In contrast, modular systems are attractive alternatives to integration because they can be tailored for different applications piecewise and without redesigning every element of the system. We present a method for reversibly coupling hard materials to soft lithography defined systems through self-aligning O-ring features thereby enabling easy interfacing of complex-valve-based systems with simpler detachable units. Using this scheme, we demonstrate the seamless interfacing of a PDMS-based fluid control module with hard polymer chips. In our system, 32 self-aligning O-ring features protruding from the PDMS fluid control module form chip-to-control module interconnections which are sealed by tightening four screws. The interconnection method is robust and supports complex fluidic operations in the reversibly attached passive chip. In addition, we developed a double-sided molding method for fabricating PDMS devices with integrated through-holes. The versatile system facilitates a wide range of applications due to the modular approach, where application specific passive chips can be readily attached to the flow control module.

  18. Test of time-reversal invariance at COSY

    Energy Technology Data Exchange (ETDEWEB)

    Valdau, Yury [Helmholtz Institut fuer Strahlen- und Kernphysik, Bonn Univ. (Germany); National Research Center ' ' Kurchatov Institute' ' Petersburg Nuclear Physics Institute B.P. Konstantinov, Gatchina (Russian Federation); Eversheim, Dieter [Helmholtz Institut fuer Strahlen- und Kernphysik, Bonn Univ. (Germany); Lorentz, Bernd [Forschungszentrum Juelich, Institute fuer Kernphysik (Germany)

    2016-07-01

    The experiment to test the Time Reversal Invariance at Cosy (TRIC) is under the preparation by the PAX collaboration. It is planned to improve present limit on the T-odd P-even interaction by at least one order of magnitude using a unique genuine null observable available in double polarized proton-deuteron scattering. The TRIC experiment is planned as a transmission experiment using a tensor polarized deuterium target placed at the internal target place of the Cooler-Synchrotron COSY-Juelich. Total double polarized cross section will be measured observing a beam current change due to the interaction of a polarized proton beam with an internal tensor polarized deuterium target from the PAX atomic beam source. Hence, in this experiment COSY will be used as an accelerator, detector and ideal zero degree spectrometer. In addition to the high intensity polarized proton beam and high density polarized deuterium target, a new high precision beam current measurement system will be prepared for the TRIC experiment. In this report status of all the activities of PAX collaboration towards realization of the TRIC experiment will be presented.

  19. Acute effects of cocaine and cannabis on reversal learning as a function of COMT and DRD2 genotype.

    Science.gov (United States)

    Spronk, Desirée B; Van der Schaaf, Marieke E; Cools, Roshan; De Bruijn, Ellen R A; Franke, Barbara; van Wel, Janelle H P; Ramaekers, Johannes G; Verkes, Robbert J

    2016-01-01

    Long-term cannabis and cocaine use has been associated with impairments in reversal learning. However, how acute cannabis and cocaine administration affect reversal learning in humans is not known. In this study, we aimed to establish the acute effects of administration of cannabis and cocaine on valence-dependent reversal learning as a function of DRD2 Taq1A (rs1800497) and COMT Val108/158Met (rs4680) genotype. A double-blind placebo-controlled randomized 3-way crossover design was used. Sixty-one regular poly-drug users completed a deterministic reversal learning task under the influence of cocaine, cannabis, and placebo that enabled assessment of both reward- and punishment-based reversal learning. Proportion correct on the reversal learning task was increased by cocaine, but decreased by cannabis. Effects of cocaine depended on the DRD2 genotype, as increases in proportion correct were seen only in the A1 carriers, and not in the A2/A2 homozygotes. COMT genotype did not modulate drug-induced effects on reversal learning. These data indicate that acute administration of cannabis and cocaine has opposite effects on reversal learning. The effects of cocaine, but not cannabis, depend on interindividual genetic differences in the dopamine D2 receptor gene.

  20. Multiple reversal olfactory learning in honeybees

    Directory of Open Access Journals (Sweden)

    Theo Mota

    2010-07-01

    Full Text Available In multiple reversal learning, animals trained to discriminate a reinforced from a non-reinforced stimulus are subjected to various, successive reversals of stimulus contingencies (e.g. A+ vs. B-, A- vs. B+, A+ vs. B-. This protocol is useful to determine whether or not animals learn to learn and solve successive discriminations faster (or with fewer errors with increasing reversal experience. Here we used the olfactory conditioning of proboscis extension reflex to study how honeybees Apis mellifera perform in a multiple reversal task. Our experiment contemplated four consecutive differential conditioning phases involving the same odors (A+ vs. B- to A- vs. B+ to A+ vs. B- to A- vs. B+. We show that bees in which the weight of reinforced or non-reinforced stimuli was similar mastered the multiple olfactory reversals. Bees which failed the task exhibited asymmetric responses to reinforced and non-reinforced stimuli, thus being unable to rapidly reverse stimulus contingencies. Efficient reversers did not improve their successive discriminations but rather tended to generalize their choice to both odors at the end of conditioning. As a consequence, both discrimination and reversal efficiency decreasedalong experimental phases. This result invalidates a learning-to-learn effect and indicates that bees do not only respond to the actual stimulus contingencies but rather combine these with an average of past experiences with the same stimuli.  

  1. Magnetic reversals from planetary dynamo waves.

    Science.gov (United States)

    Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

    2016-11-24

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

  2. Reverse pitch fan with divided splitter

    Science.gov (United States)

    Smith, L. H., Jr. (Inventor)

    1977-01-01

    A guide vane arrangement is described for improving gas turbine performance in the reverse thrust mode. This flow straightening method produces low losses in the fluid entering a core engine during reverse thrust operations and allows large supercharging of the core engine during forward thrust.

  3. Reversal of laryngotracheal separation in paediatric patients.

    LENUS (Irish Health Repository)

    Young, Orla

    2012-02-01

    OBJECTIVE: Laryngotracheal separation (LTS) is an effective and reliable definitive treatment for intractable aspiration. A major advantage of this treatment for intractable aspiration is its\\' potential reversibility. Should the underlying disorder improve, a reversal of the procedure may be attempted. This has been successfully achieved in the adult population. To our knowledge, no previous cases have been reported of successful reversal of LTS in children. METHODS: A retrospective review from 2003 to 2010 identified four cases of intractable aspiration treated with LTS in our department. Two of these patients displayed objective evidence of sufficient recovery of their underlying aspiration to consider reversal. Patient selection for reversal was dependent upon successful oral intake for 9 months along with videofluoroscopic evidence of normal or minimally impaired swallow. RESULTS: Two children who were successfully treated for intractable aspiration with LTS demonstrated objective evidence of recovery sufficient to attempt reversal. Both children underwent successful surgical reversal of LTS using a cricotracheal resection with end-to-end anastamosis, similar to that used in treatment of subglottic stenosis. Both children can now tolerate oral diet and their speech and language development is in line with their overall developmental level. CONCLUSIONS: Laryngotracheal separation is an effective and reliable definitive treatment for intractable aspiration facilitating protection of the airway and allowing safe swallowing with unimpeded respiration, but with the major drawback of loss of phonation. To our knowledge, we document the first two cases of successful LTS reversal in children.

  4. Online Reverse Auctions for Procurement of Services

    NARCIS (Netherlands)

    U.L. Radkevitch (Uladzimir)

    2008-01-01

    textabstractOnline reverse auctions, in which a buyer seeks to select a supplier and suppliers compete for contracts by bidding online, revolutionized corporate procurement early this century. Shortly after they had been pioneered by General Electric, many companies rushed to adopt reverse auctions

  5. Reverse Galilean telescopic spectacles in unilateral aphakia.

    Science.gov (United States)

    Krefman, R A

    1981-09-01

    Minimizing aniseikonia in unilateral aphakia is often a difficult task. A case is presented in which a patient preferred a reverse Galilean telescopic spectacle of his own design to a contact lens. The design of the spectacles and the patient's visual performance with them are described. A reverse Galilean telescopic spectacle should not be excluded from the therapeutic alternatives in unilateral aphakia.

  6. Probabilistic Reversible Automata and Quantum Automata

    OpenAIRE

    Golovkins, Marats; Kravtsev, Maksim

    2002-01-01

    To study relationship between quantum finite automata and probabilistic finite automata, we introduce a notion of probabilistic reversible automata (PRA, or doubly stochastic automata). We find that there is a strong relationship between different possible models of PRA and corresponding models of quantum finite automata. We also propose a classification of reversible finite 1-way automata.

  7. Preference Reversals: Violations of Unidimensional Procedure Invariance

    NARCIS (Netherlands)

    P.F.M. Stalmeier (Peep); P.P. Wakker (Peter); Th.G.G. Bezembinder (Thom)

    1997-01-01

    textabstractPreference reversals have usually been explained by weighted additive models, in which different tasks give rise to different importance weights for the stimulus attributes, resulting in contradictory trade-offs. This article presents a preference reversal of a more extreme nature. Let

  8. Preference reversals: violations of unidimensional procedure invariance

    NARCIS (Netherlands)

    Wakker, P.P.; Stalmeijer, P.F.M.; Bezembinder, T.G.G.

    1997-01-01

    Preference reversals have usually been explained by weighted additive models, in which different tasks give rise to different importance weights for the stimulus attributes, resulting in contradictory tradeoffs. This article presents a preference reversal of a more extreme nature. Let (10, 5 Migr)

  9. Reversible logic gates on Physarum Polycephalum

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Andrew [University of Information Technology and Management, Sucharskiego 2, Rzeszow, 35-225 (Poland)

    2015-03-10

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

  10. Reverse Logistics - a review of case studies

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert); S.D.P. Flapper

    2003-01-01

    textabstractProducts, components, materials and other equipment stream forward and back wards and back in their supply chains. Reverse Logistics deals with the processes associated with the reverse stream from users/owners to re-users. This paper provides a review and content analysis of scientific

  11. Experimental Investigation of Solar Powered Reverse Osmosis ...

    African Journals Online (AJOL)

    fire7-

    Pollution and over exploitation of groundwater aquifer and surface water have led to a decrease ... favoring for implementing solar photovoltaic (PV) reverse osmosis (RO) desalination technology. The fast development of solar energy, especially photovoltaic, ... Among desalination technologies, reverse osmosis is rapidly.

  12. Manual Colostomy Reversals Following Wide Colorectal Resections ...

    African Journals Online (AJOL)

    Manual Colostomy Reversals Following Wide Colorectal Resections at Poorly Equipped Surgical Facilities. EBFK Odimba, M Nthele, M Mbambiko. Abstract. Background: The decision for colostomy reversal is usually not easy and often reflects patient's desire, fully analyzed and agreed by the surgeon. The unavailability of ...

  13. Dissipative particle dynamics studies of doxorubicin-loaded micelles assembled from four-arm star triblock polymers 4AS-PCL-b-PDEAEMA-b-PPEGMA and their pH-release mechanism.

    Science.gov (United States)

    Nie, Shu Yu; Sun, Yao; Lin, Wen Jing; Wu, Wen Sheng; Guo, Xin Dong; Qian, Yu; Zhang, Li Juan

    2013-10-31

    Dissipative particle dynamics (DPD) simulation was applied to investigate the microstructures of the micelles self-assembled from pH-sensitive four-arm star triblock poly(ε-caprolactone)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (4AS-PCL-b-PDEAEMA-b-PPEGMA). In the optimized system, the micelles have a core-mesosphere-shell three-layer structure. The drug-loading process and its distribution at different formulations in the micelles were studied. The results show that DOX molecules distributed in the core and the interface between the core and the mesosphere, suggesting the potential encapsulation capacity of DOX molecules. More drugs were loaded in the micelles with the increase in DOX, and the size of micelles became larger. However, some openings start to generate on the PEG shell when the DOX reaches a certain concentration. By changing the pH values of the system, different morphologies of the micelles were acquired after the pH-sensitive blocks PDEAEMA were protonated, the mechanism of which was also analyzed through correlating functions. The results indicated that the sudden increase in solubility parameter of the pH-sensitive blocks and the swelling of the micelles were the key factors on the change of morphologies. Furthermore, with the decrease in pH value, the number and size of the cracks on the surface of the micelles were larger, which may have a direct effect on the drug release. In conclusion, 4AS-PCL-b-PDEAEMA-b-PPEGMA has great promising applications in delivering hydrophobic anticancer drugs for improved cancer therapy.

  14. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2018-01-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  15. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2017-10-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  16. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    Abstract Babu and Chowdhury [H.M.H. Babu, A.R. Chowdhury, Design of a compact reversible binary coded decimal adder circuit, Journal of Systems Architecture 52 (5) (2006) 272-282] recently proposed, in this journal, a reversible adder for binary-coded decimals. This paper corrects and optimizes....... Keywords: Reversible logic circuit; Full-adder; Half-adder; Parallel adder; Binary-coded decimal; Application of reversible logic synthesis......) BCD addition, the circuit delay of 49 gates is significantly lower than is the number of bits used for the BCD representation. A complete set of reversible half- and full-adders for n-bit binary numbers and m-decimal BCD numbers is presented. The results show that special-purpose design pays off...

  17. Alternate Double Single Track Lines

    Energy Technology Data Exchange (ETDEWEB)

    Moraga Contreras, P.; Grande Andrade, Z.; Castillo Ron, E.

    2016-07-01

    The paper discusses the advantages and shortcomings of alternate double single track (ADST) lines with respect to double track lines for high speed lines. ADST lines consists of sequences of double and single track segments optimally selected in order to reduce the construction and maintenance costs of railway lines and to optimize the timetables used to satisfy a given demand. The single tracks are selected to coincide with expensive segments (tunnels and viaducts) and the double tracks are chosen to coincide with flat areas and only where they are necessary. At the same time, departure times are adjusted for trains to cross at the cheap double track segments. This alternative can be used for new lines and also for existing conventional lines where some new tracks are to be constructed to reduce travel time (increase speed). The ADST proposal is illustrated with some examples of both types (new lines and where conventional lines exist), including the Palencia-Santander, the Santiago-Valparaíso-Viña del Mar and the Dublin-Belfast lines, where very important reductions (90 %) are obtained, especially where a railway infrastructure already exist. (Author)

  18. The structure of PX{sub 3} (X = Cl, Br, I) molecular liquids from X-ray diffraction, molecular dynamics simulations, and reverse Monte Carlo modeling

    Energy Technology Data Exchange (ETDEWEB)

    Pothoczki, Szilvia, E-mail: pothoczki.szilvia@wigner.mta.hu; Temleitner, László; Pusztai, László [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege M. út 29-33, 1121 Budapest (Hungary)

    2014-02-07

    Synchrotron X-ray diffraction measurements have been conducted on liquid phosphorus trichloride, tribromide, and triiodide. Molecular Dynamics simulations for these molecular liquids were performed with a dual purpose: (1) to establish whether existing intermolecular potential functions can provide a picture that is consistent with diffraction data and (2) to generate reliable starting configurations for subsequent Reverse Monte Carlo modelling. Structural models (i.e., sets of coordinates of thousands of atoms) that were fully consistent with experimental diffraction information, within errors, have been prepared by means of the Reverse Monte Carlo method. Comparison with reference systems, generated by hard sphere-like Monte Carlo simulations, was also carried out to demonstrate the extent to which simple space filling effects determine the structure of the liquids (and thus, also estimating the information content of measured data). Total scattering structure factors, partial radial distribution functions and orientational correlations as a function of distances between the molecular centres have been calculated from the models. In general, more or less antiparallel arrangements of the primary molecular axes that are found to be the most favourable orientation of two neighbouring molecules. In liquid PBr{sub 3} electrostatic interactions seem to play a more important role in determining intermolecular correlations than in the other two liquids; molecular arrangements in both PCl{sub 3} and PI{sub 3} are largely driven by steric effects.

  19. Unified double- and single-sided homogeneous Green's function representations.

    Science.gov (United States)

    Wapenaar, Kees; van der Neut, Joost; Slob, Evert

    2016-06-01

    In wave theory, the homogeneous Green's function consists of the impulse response to a point source, minus its time-reversal. It can be represented by a closed boundary integral. In many practical situations, the closed boundary integral needs to be approximated by an open boundary integral because the medium of interest is often accessible from one side only. The inherent approximations are acceptable as long as the effects of multiple scattering are negligible. However, in case of strongly inhomogeneous media, the effects of multiple scattering can be severe. We derive double- and single-sided homogeneous Green's function representations. The single-sided representation applies to situations where the medium can be accessed from one side only. It correctly handles multiple scattering. It employs a focusing function instead of the backward propagating Green's function in the classical (double-sided) representation. When reflection measurements are available at the accessible boundary of the medium, the focusing function can be retrieved from these measurements. Throughout the paper, we use a unified notation which applies to acoustic, quantum-mechanical, electromagnetic and elastodynamic waves. We foresee many interesting applications of the unified single-sided homogeneous Green's function representation in holographic imaging and inverse scattering, time-reversed wave field propagation and interferometric Green's function retrieval.

  20. Reversible machine code and its abstract processor architecture

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert; Yokoyama, Tetsuo

    2007-01-01

    A reversible abstract machine architecture and its reversible machine code are presented and formalized. For machine code to be reversible, both the underlying control logic and each instruction must be reversible. A general class of machine instruction sets was proven to be reversible, building ...... on our concept of reversible updates. The presentation is abstract and can serve as a guideline for a family of reversible processor designs. By example, we illustrate programming principles for the abstract machine architecture formalized in this paper....