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Rushi K Talati, Joelle A Hallak, Faris I Karas, Jose de la Cruz, M Soledad Cortina
PURPOSE: Retroprosthetic membrane (RPM) formation is the most common complication after Boston type 1 keratoprosthesis (KPro) implantation. It affects visual acuity and can predispose to corneal melt. Two KPro backplate materials are available: titanium and polymethyl methacrylate (PMMA). This study investigates the influence of the KPro backplate material on visually significant RPM formation. METHODS: A retrospective case-control-matched study involving 40 patients; 20 eyes implanted with a titanium backplate KPro were case-matched with 20 eyes implanted with a PMMA backplate KPro between 2007 and 2015 with 1-year minimum follow-up...
November 14, 2017: Cornea
Steffen Vowinkel, Stephen Paul, Torsten Gutmann, Markus Gallei
The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique...
November 15, 2017: Nanomaterials
Junbo Li, Lijuan Liang, Ju Liang, Wenlan Wu, Huiyun Zhou, Jinwu Guo
A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)-block-poly(N-isopropylacrylamide) modified gold nanoparticles (PMAA-b-PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG-b-PMMPImB) via polyion complex of PMMA and PMMPImB. After removing the Au NPs template, asymmetric PICsomes composed of a PNIPAm inner-shell, PIC wall, and PEG outer-corona were obtained...
November 13, 2017: Nanomaterials
Monali N Basutkar, Saumil Samant, Joseph Strzalka, Kevin G Yager, Gurpreet Singh, Alamgir Karim
Template-free directed self-assembly of ultrathin (~10's nm) lamellar block copolymer (l-BCP) films of high-interfacial area into vertically oriented nanodomains holds much technological relevance for fabrication of next-generation devices from nanoelectronics to nanomembranes due to domain interconnectivity and high interfacial area. We report for the first time, the formation of full thru-thickness vertically oriented lamellar domains in 100 nm thin polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) films on quartz substrate, achieved without any PMMA-block wetting layer formation, quartz surface modification (templating chemical, topographical) or system modifications (added surfactant, top-layer coat)...
November 14, 2017: Nano Letters
J Bryan McLaughlin, Van Ramos, Douglas P Dickinson
PURPOSE: To compare the shrinkage of denture bases fabricated by three methods: CAD/CAM, compression molding, and injection molding. The effect of arch form and palate depth was also tested. MATERIALS AND METHODS: Nine titanium casts, representing combinations of tapered, ovoid, and square arch forms and shallow, medium, and deep palate depths, were fabricated using electron beam melting (EBM) technology. For each base fabrication method, three poly(vinyl siloxane) impressions were made from each cast, 27 dentures for each method...
November 14, 2017: Journal of Prosthodontics: Official Journal of the American College of Prosthodontists
Anthony Asemota, Gabriel F Santiago, Susan Zhong, Chad R Gordon
PURPOSE: Temporal hollowing deformity (THD) is a visible concavity/convexity in the temporal fossa; a complication often seen following neurosurgical/craniofacial procedures. Although numerous techniques have been described, no study to date has shown the healthcare costs associated with temporal hollowing correction surgery. Thus, the purpose here is to compare and contrast the direct costs related to temporal cranioplasty using various methods including: liquid poly-methyl-methacrylate (PMMA) implants with screw fixation, prebent, modified titanium mesh implants, and customized cranial implants (CCIs) with dual-purpose design...
November 9, 2017: Journal of Craniofacial Surgery
Alfin Kurniawan, Chintya Effendi, Meng-Jiy Wang
The incorporation of inorganic materials into electrospun nanofibers has recently gained considerable attention for the development of ECM-like scaffolds with improved mechanical properties and enhanced biological functions for tissue engineering applications. In this study, polymer-inorganic composite fibers consisting of poly(2-ethyl-2-oxazoline) (PEOXA) and tetrabutyl titanate (TBT) as the titanium precursor were successfully fabricated through a combined sol-gel/electrospinning approach. PEOXA/Ti(OR)n composite fibers were obtained with varying amounts of polymer and titanium precursors...
November 14, 2017: Journal of Tissue Engineering and Regenerative Medicine
Hirotaka Yamada, Ferhat Aydinoglu, Yaoze Liu, Ripon Kumar Dey, Bo Cui
One of the important challenges in electron beam lithography is nanofabrication on non-flat or irregular surfaces. Although spin coating is the most popular technique for resist coating, it is not suitable for non-flat, irregular substrates because uniform film cannot be achieved on those surfaces. Here, it is demonstrated that single layer surface-grafted PMMA can be used as negative tone e-beam resist, and it can be applied for non-flat, irregular surfaces as well as flat, conventional surfaces. Although it is well known that heavily exposed PMMA undergoes cross-linking and works as negative tone e-beam resist when developed by solvent, solvent does not work as a developer for negative-tone single layer surface-grafted PMMA...
November 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Piotr Miluski, Marcin Kochanowicz, Jacek Zmojda, Dominik Dorosz
The fluorescent dyes allow new optical applications in polymer-based optical fibre technology. The article presents highly fluorescent 1,4-Bis(2-methylstyryl)benzene doped poly(methyl methacrylate) (PMMA) fibre. The multi-peak (422, 450, 488nm) fluorescence spectrum of the bulk specimen under 355nm excitation is presented. The polymerization and fibre drawing process is also shown. The fluorescent properties vs. fibre length at excitation 405nm are investigated. Significant spectrum shape changes and red shift phenomena of individual peaks are presented using one end excitation and fibre cutting method measurements for fibre length 2-90cm...
November 3, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
L Karnam, L Brambilla, M Del Zoppo, C Bertarelli
Anthracene tetracene-doped crystals (TA) dispersed in a thin polymer film matrix have been reported as efficient down converting systems based on Förster Resonance Energy Transfer (FRET) which occurs efficiently from donor (anthracene) to acceptor (tetracene) molecules. In this work, we demonstrate that the efficiency of this system can be further improved by a metal-enhanced FRET, which is obtained by incorporating metal nanoparticles into the polymer matrix. We report on the preparation and optical responses of polymeric transparent thin films where dodecanethiol-capped silver or gold nanoparticles are dispersed with TA in a polymethylmethacrylate (PMMA) matrix...
November 10, 2017: Physical Chemistry Chemical Physics: PCCP
Weijia Fan, Masatoshi Tosaka, Shigeru Yamago, Michael F Cunningham
Ab initio emulsion polymerization of methyl methacrylate (MMA) using a water-soluble organotellurium chain transfer agent in the presence of the surfactant Brij 98 in water is reported. Polymerization proceeded under both thermal and visible light-irradiation conditions giving poly(methyl methacrylate) (PMMA) with controlled molecular weight and low dispersity (Đ<1.5). Despite the formation of an opaque latex, the photo-activation of the organotellurium dormant species took place efficiently as demonstrated by the quantitative monomer conversion and temporal control...
November 10, 2017: Angewandte Chemie
Debashish Mukherji, Carlos M Marques, Torsten Stuehn, Kurt Kremer
Establishing a link between macromolecular conformation and microscopic interaction is a key to understand properties of polymer solutions and for designing technologically relevant "smart" polymers. Here, polymer solvation in solvent mixtures strike as paradoxical phenomena. For example, when adding polymers to a solvent, such that all particle interactions are repulsive, polymer chains can collapse due to increased monomer-solvent repulsion. This depletion induced monomer-monomer attraction is well known from colloidal stability...
November 9, 2017: Nature Communications
Huiling Liu, Bin Liu, Chunxia Gao, Bin Meng, Huilin Yang, Haiyang Yu, Lei Yang
PURPOSE: Poly(methyl methacrylate) (PMMA) cement is widely used for percutaneous kyphoplasty and vertebroplasty (PKP and PVP) but possesses formidable shortcomings due to non-degradability. Here, a biodegradable replacement is developed. METHODS: Calcium phosphate cement (CPC) was redesigned by incorporating starch and BaSO4 (new cement named as CPB). The biomechanical, biocompatibility, osseointegrative and handling properties of CPB were systematically evaluated in vitro and in vivo by the models of osteoporotic sheep vertebra, rat subcutaneous implantation and rat femoral defect...
November 7, 2017: International Orthopaedics
Lin Xu, Dipankar Bandyopadhyay, Puchalapalli Dinesh Sankar Reddy, Ashutosh Sharma, Sang Woo Joo
A 'giant' slip dynamics was engineered to a highly confined interface of a dewetting polymethylmethacrylate (PMMA) ultrathin film by introducing a lubricating viscous polystyrene (PS) sublayer. The crossover of regimes from no-slip to giant-slip was engendered by tuning the viscosity and thickness of the sublayer. A long-range hole-rim interaction with increase in slippage on the PMMA-PS interface transformed the circular holes on the PMMA surface into the noncircular faceted ones. The extent of the slippage and the transition of the length scales from slip-dominated to no-slip regime were evaluated using a general linear stability analysis...
November 7, 2017: Scientific Reports
Malcolm Gent, Héctor Muñiz Sierra, Mario Menéndez, Francisco Javier de Cos Juez
Viable recycled residual plastic (RP) product(s) must be of sufficient quality to be reusable as a plastic or source of hydrocarbons or fuel. The varied composition and large volumes of such wastes usually requires a low cost, high through-put recycling method(s) to eliminate contaminants. Cyclone separation of plastics by density is proposed as a potential method of achieving separations of specific types of plastics. Three ground calcite separation medias of different grain size distributions were tested in a cylindrical cyclone to evaluate density separations at 1...
October 26, 2017: Waste Management
Olwyn R Mahon, Sarah O'Hanlon, Clare C Cunningham, Geraldine M McCarthy, Christopher Hobbs, Valeria Nicolosi, Daniel J Kelly, Aisling Dunne
Total joint replacements (TJR) are costly procedures required to relieve pain and restore function in patients suffering from end-stage arthritis. Despite great progress in the development and durability of TJRs, the generation of prosthesis-associated wear particles over time leads to an inflammatory cascade which culminates in periprosthetic osteolysis. Studies suggest that wear particles drive the polarization/differentiation of immature macrophages towards a pro-inflammatory M1 phenotype rather than an anti-inflammatory M2 phenotype associated with normal bone and wound healing...
November 2, 2017: Acta Biomaterialia
Michael Pujari-Palmer, Celine Robo, Cecilia Persson, Philip Procter, Håkan Engqvist
Disease and injuries that affect the skeletal system may require surgical intervention and internal fixation, i.e. orthopedic plate and screw insertion, to stabilize the injury and facilitate tissue repair. If the surrounding bone quality is poor the screws may migrate, or the bone may fail, resulting in fixation failure. While numerous studies have shown that cement augmentation of the interface between bone and implant can increase screw pull-out force, the physical properties of cement that influence pull-out force have not been investigated...
October 13, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Junqing Zhao, Hang Guo, Yao Kun Pang, Fengben Xi, Zhi Wei Yang, Guoxu Liu, Tong Guo, Guifang Dong, Chi Zhang, Zhong Lin Wang
Flexible electronics has attracted enormous interest in wearable electronics and human-machine interfacing. Here, a flexible organic tribotronic transistor (FOTT) without a top gate electrode has been demonstrated. The FOTT is fabricated on a flexible polyethylene terephthalate film using the p-type pentacene and poly(methyl methacrylate)/Cytop composites as the conductive channel and dielectric layer, respectively. The charge carriers can be modulated by the contact electrification between the dielectric layer and a mobile triboelectric layer...
November 8, 2017: ACS Nano
Zhao Yang, Lei Chen, Yuxin Hao, Yuan Zang, Xiong Zhao, Lei Shi, Yang Zhang, Yafei Feng, Chao Xu, Faqi Wang, Xinli Wang, Bowen Wang, Chenxin Liu, Yufei Tang, Zixiang Wu, Wei Lei
Poly(methyl methacrylate) (PMMA), the most common bone cement, has been used as a graft substitute in orthopedic surgeries such as vertebroplasty. However, an undesirable minor crack in the bone-cement interface provoked by shrinkage during polymerization and high elastic modulus of conventional PMMA bone cement dramatically increases the risk of vertebral body refracture postsurgery. Thus, herein, a hydrophilous expandable bone cement was synthesized based on a PMMA commercial cement (Mendec Spine Resin), acrylic acid (AA), and styrene (St)...
November 10, 2017: ACS Applied Materials & Interfaces
Tammer Elmarsafi, John S Steinberg, Paul J Kim, Christopher E Attinger, Karen K Evans
INTRODUCTION: Charcot Neuroarthropathy is a complex lower extremity pathology which predisposes the afflicted limb to ulcerations, osteomyelitis, and risk of major amputation. Charcot Neuroarthropathy often requires osseous reconstruction, which can be complicated with osteomyelitis and hardware infection. When soft tissue and osseous deficits must be concomitantly addressed, the use of PMMA spacers can be combined with free tissue transfers. PRESENTATION OF CASE: 71year old Caucasian male with Diabetic Charcot Neuroarthopathy underwent osseous reconstruction with internal hardware...
October 4, 2017: International Journal of Surgery Case Reports
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