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https://www.readbyqxmd.com/read/28443918/ph-responsiveness-of-hydrogels-formed-by-telechelic-polyampholytes
#1
Margarita A Dyakonova, George Gotzamanis, Bart-Jan Niebuur, Natalya S Vishnevetskaya, Konstantinos N Raftopoulos, Zhenyu Di, Sergey K Filippov, Constantinos Tsitsilianis, Christine M Papadakis
We investigate the influence of pH on the rheological and structural properties of hydrogels formed by hydrophobic association of the sticky ends of the triblock terpolymer poly(methyl methacrylate)-b-poly(2-(diethylamino)ethyl methacrylate-co-methacrylic acid)-b-poly(methyl methacrylate) (PMMA-b-P(DEA-co-MAA)-b-PMMA). The middle block is a weak polyampholyte having a pH dependent charge density and sign, which enables tuning of the rheological and structural properties by pH variation. Small-angle neutron scattering (SANS) studies of solutions in D2O at 0...
April 26, 2017: Soft Matter
https://www.readbyqxmd.com/read/28443902/an-internal-magnetic-field-strategy-to-reuse-pulverized-active-materials-for-high-performance-a-magnetic-three-dimensional-ordered-macroporous-tio2-copt-%C3%AE-fe2o3-nanocomposite-anode
#2
Yiping Tang, Liang Hong, Jiquan Li, Guangya Hou, Huazhen Cao, Liankui Wu, Guoqu Zheng, Qingliu Wu
A ferromagnetic three-dimensional ordered macroporous TiO2/CoPt/α-Fe2O3 (3DOMTCF) nanocomposite was synthesized via a sol-gel approach templated by poly(methyl methacrylate) (PMMA) microspheres. After magnetization, it exhibited an extremely high reversible capacity and a long cycle life, which were ascribed to the internal magnetic field for reusing pulverized active materials and its unique structure.
April 26, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28442174/microstructural-alterations-owing-to-handling-of-bovine-pericardium-to-manufacture-bioprosthetic-heart-valves-a-potential-risk-for-cusp-dehiscence
#3
J Mao, Y Wang, E Philippe, T Cianciulli, I Vesely, D How, J-M Bourget, L Germain, Z Zhang, R Guidoin
INTRODUCTION: Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis. MATERIAL AND METHOD: Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures...
April 22, 2017: Morphologie: Bulletin de L'Association des Anatomistes
https://www.readbyqxmd.com/read/28441871/frequency-dependent-solvent-impedance-and-colloid-micro-electrophoresis-measurements-in-partially-polar-solvents
#4
Edward Hayden, Zena Aljabal, Anand Yethiraj
We carry out frequency-dependent solvent impedance measurements and AC colloid micro-electrophoresis experiments in partially polar solvents in the low-frequency regime (0.25 Hz $\le f \le $ 10 Hz). Solvent electrode polarization effects are quantified first in partially polar solvent mixtures containing bromocyclohexane (CHB). We find that the polarization capacitance from electrode polarization exhibits a clear power law behavior $C_p = C_{p0} f^{-m}$ with power law exponent $m = 0.25 \pm 0.04$. Once we account for electrode polarization effects, we are able to obtain quantitative mobilities in the low-frequency regime from our AC micro-electrophoresis measurements: for these measurements, we use PMMA colloids that are gravitationally confined to a plane while suspended in a low-polar solvent mixture of cis-trans decahydronapthalene (decalin) and bromocyclohexane (CHB)...
April 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28438025/fusion-of-polymeric-material-binding-peptide-to-cell-adhesion-artificial-proteins-enhances-their-biological-function
#5
Tomonori Waku, Yuko Imanishi, Yuta Yoshino, Shigeru Kunugi, Takeshi Serizawa, Naoki Tanaka
Orientation-controlled protein immobilization on a solid substrate surface is important for the development of biomedical materials such as scaffolds used in tissue engineering. In this study, the authors demonstrated that the introduction of material-binding peptides (MBPs) in Arg-Gly-Asp (RGD)-fused artificial proteins called blocking peptide fragment (BPF), which are fragments (residues 419-607) of the molecular chaperone DnaK, enhances the oriented adsorption of proteins on the polymer surface and improves their cell adhesion capability...
April 24, 2017: Biointerphases
https://www.readbyqxmd.com/read/28436858/a-spectral-ct-method-to-directly-estimate-basis-material-maps-from-experimental-photon-counting-data
#6
Taly Schmidt, Rina Barber, Emil Sidky
The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the effective energy-window spectra using a calibration procedure. The amplitudes of the estimated spectra were further optimized as part of the reconstruction process to reduce ring artifacts...
April 24, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28436501/bis-zn-ii-salphen-complexes-bearing-pyridyl-functionalized-ligands-for-efficient-organic-light-emitting-diodes-oleds
#7
Jiang Zhao, Feifan Dang, Boao Liu, Yong Wu, Xiaolong Yang, Guijiang Zhou, Zhaoxin Wu, Wai-Yeung Wong
Inspired by the emissive features of Zn(II) complexes based on bis-Schiff base ligands, bis-Zn(II) salphen complexes bearing pyridyl functionalized ligands have been successfully synthesized. Their photophysical features, electrochemical behavior and electroluminescent (EL) properties have been investigated in detail. The functionalized bis-Zn(II) salphen complexes can exhibit high thermal stability up to 417 °C, and their photoluminescence (PL) spectra show a maximal emission wavelength peak at ca. 565 nm both in solution and PMMA doped films...
April 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28435554/influence-of-soluble-fillers-in-improving-porosity-of-handmade-antibiotic-impregnated-polymethyl-methacrylate-pmma-beads-an-in-vitro-study
#8
H N Rasyid, S Soegijoko
There have been many investigations on non-biodegradable materials acting as an antibiotic carrier for local drug delivery systems based on polymethyl methacrylate (PMMA) beads. However, the material is non-degradable and non-porous so that less than 5% of the encapsulated drug is released. In order to obtain better release of the antibiotics, greater porosity of the beads would be required. Adding fillers could increase the bead's porosity, thus improving the antibiotic release from the beads. The purpose of the study is to optimize release kinetics of gentamicin from handmade beads by adding fillers such as glycine and sodium chloride in different concentrations...
July 2016: Malaysian Orthopaedic Journal
https://www.readbyqxmd.com/read/28431467/influence-of-glycosylation-on-interfacial-properties-of-recombinant-mucins-adsorption-surface-forces-and-friction
#9
Junxue An, Chunsheng Jin, Andra Dėdinaitė, Jan Holgersson, Niclas G Karlsson, Per M Claesson
Interfacial properties of two brush-with-anchor mucins, C-P55 and C-PSLex, have been investigated at the aqueous solution/poly(methyl methacrylate) (PMMA) interface. Both are recombinant mucin-type fusion proteins, produced by fusing the glycosylated mucin part of P-selectin glycoprotein ligand-1 (PSLG-1) to the Fc part of a mouse immunoglobulin in two different cells. They are mainly expressed as dimers upon production. Analysis of the O-glycans shows that the C-PSLex mucin has the longer and more branched side chains, but C-P55 has slightly higher sialic acid content...
April 26, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28429875/effect-of-untreated-zirconium-oxide-nanofiller-on-the-flexural-strength-and-surface-hardness-of-autopolymerized-interim-fixed-restoration-resins
#10
Abdolhamid Alhavaz, Maryam Rezaei Dastjerdi, Arman Ghasemi, Azade Ghasemi, Abolfazl Alizadeh Sahraei
OBJECTIVE: Autopolymerized poly methyl methacrylate (PMMA) resin is commonly used for the construction of interim restorations; however, it has less than optimal mechanical properties. In this article, we evaluated the reinforcing effect of adding untreated zirconia nanoparticles on the flexural strength and surface hardness of this resin. METHODS: A total of 80 specimens were fabricated. Forty each were used for the flexural strength test and for the surface hardness test...
April 21, 2017: Journal of Esthetic and Restorative Dentistry
https://www.readbyqxmd.com/read/28429805/bio-inspired-large-scale-highly-scattering-films-for-nanoparticle-alternative-white-surfaces
#11
Julia Syurik, Radwanul Hasan Siddique, Antje Dollmann, Guillaume Gomard, Marc Schneider, Matthias Worgull, Gabriele Wiegand, Hendrik Hölscher
Inspired by the white beetle of the genus Cyphochilus, we fabricate ultra-thin, porous PMMA films by foaming with CO2 saturation. Optimising pore diameter and fraction in terms of broad-band reflectance results in very thin films with exceptional whiteness. Already films with 60 µm-thick scattering layer feature a whiteness with a reflectance of 90%. Even 9 µm thin scattering layers appear white with a reflectance above 57%. The transport mean free path in the artificial films is between 3.5 µm and 4 µm being close to the evolutionary optimised natural prototype...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28425155/effect-of-platinum-on-sintering-morphology-of-porous-ysz-ceramics
#12
Pan Fang, Junmei Wang, Xian Li, Shijie Wu, Wenlei Zhang, Sufang Li
Platinum/yttria-stabilized zirconia (Pt/YSZ) porous ceramics were prepared by sintering of the Pt/PMMA/YSZ stripe-like membrane with a porogen of spherical polymethyl methacrylate (PMMA) and a precursor of platinum (Pt) of chloroplatinic acid. The microstructure of raw and processed material and Pt/ZrO2 calcination process at different sintering temperatures were investigated. The results showed that the spherically porous structure of Pt/YSZ was observed at a sintering temperature below 400 °C due to the thermal decomposition of PMMA...
April 19, 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/28422244/adhesion-and-friction-in-polymer-films-on-solid-substrates-conformal-sites-analysis-and-corresponding-surface-measurements
#13
Rong An, Liangliang Huang, Kenneth P Mineart, Yihui Dong, Richard J Spontak, Keith E Gubbins
In this work, we present a statistical mechanical analysis to elucidate the molecular-level factors responsible for the static and dynamic properties of polymer films. This analysis, which we term conformal sites theory, establishes that three dimensionless parameters play important roles in determining differences from bulk behavior for thin polymer films near to surfaces: a microscopic wetting parameter, αwx, defined as the ratio of polymer-substrate interaction to polymer-polymer interaction; a dimensionless film thickness, H*; and dimensionless temperature, T*...
April 19, 2017: Soft Matter
https://www.readbyqxmd.com/read/28420544/disclosing-agents-for-the-intraoperative-identification-of-biofilms-on-orthopedic-implants
#14
Joshua A Parry, Melissa J Karau, Sanjeev Kakar, Arlen D Hanssen, Robin Patel, Matthew P Abdel
BACKGROUND: Disclosing agents are dyes used in dentistry to colorize plaque (biofilm) and may offer a means for intraoperative detection of biofilms on orthopedic implants. Methylene blue (MB) stains biofilm and is safely used in orthopedic applications. Injection of MB into acutely infected prosthetic knees before debridement may enable visualization of biofilm, which could influence treatment decisions. The aims of this study were to determine if MB could be used to visualize biofilm on total knee arthroplasty (TKA) implants and to determine if MB staining has an antimicrobial effect that might interfere with subsequent culture...
March 16, 2017: Journal of Arthroplasty
https://www.readbyqxmd.com/read/28420216/fast-bragg-grating-inscription-in-pmma-polymer-optical-fibres-impact-of-thermal-pre-treatment-of-preforms
#15
Carlos A F Marques, Andreas Pospori, Gökhan Demirci, Onur Çetinkaya, Barbara Gawdzik, Paulo Antunes, Ole Bang, Pawel Mergo, Paulo André, David J Webb
In this work, fibre Bragg gratings (FBGs) were inscribed in two different undoped poly- (methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process) have a different thermal treatment...
April 18, 2017: Sensors
https://www.readbyqxmd.com/read/28419125/mammographic-compression-in-asian-women
#16
Susie Lau, Yang Faridah Abdul Aziz, Kwan Hoong Ng
OBJECTIVES: To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study. METHODS: We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area...
2017: PloS One
https://www.readbyqxmd.com/read/28418673/aberration-corrected-electron-beam-lithography-at-the-one-nanometer-length-scale
#17
Vitor Riseti Manfrinato, Aaron Stein, Lihua Zhang, Chang-Yong Nam, Kevin G Yager, Eric A Stach, Charles T Black
Patterning materials efficiently at the smallest length scales is a longstanding challenge in nanotechnology. Electron-beam lithography (EBL) is the primary method for patterning arbitrary features, but EBL has not reliably provided sub-4 nanometer patterns. The few competing techniques that have achieved this resolution are orders of magnitude slower than EBL. In this work, we employed an aberration-corrected scanning transmission electron microscope for lithography to achieve unprecedented resolution. Here we show aberration-corrected EBL at the one nanometer length scale using poly(methyl methacrylate) (PMMA), and have produced both the smallest isolated feature in any conventional resist (1...
April 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28418574/inadequacy-of-joint-aspiration-for-detection-of-persistent-periprosthetic-infection-during-two-stage-septic-revision-knee-surgery
#18
Bernd Preininger, Viktor Janz, Philipp von Roth, Andrej Trampuz, Carsten F Perka, Tilman Pfitzner
Despite the lack of validation, synovial aspiration remains a common practice during 2-stage septic revision total knee arthroplasty (TKA). The goal of this study was to investigate the diagnostic validity of synovial polymethylmethacrylate (PMMA) spacer aspiration of temporary knee arthrodesis to detect persistent periprosthetic joint infection before TKA reimplantation. This retrospective cohort study included 73 consecutive patients who underwent 2-stage septic revision TKA according to a standard protocol...
April 18, 2017: Orthopedics
https://www.readbyqxmd.com/read/28416837/-clinical-comparison-of-polymethylmethacrylate-and-bone-cement-in-the-treatment-of-osteoporotic-vertebral-compression-fractures-a-retrospective-study
#19
L P Shang, Y Tian, X G Liu
OBJECTIVE: To analyze the outcomes of patients with osteoporotic vertebral compression fractures treated with polymethylmethacrylate (PMMA) and GeneX bone cement in percutaneous kyphoplasty and to provide guidance in selecting the vertebral filling material for this procedure. METHODS: In this study, 86 patients with osteoporotic vertebral compression fractures treated at Peking University Third Hospital between June 2012 and June 2013 were retrospectively analyzed...
April 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
https://www.readbyqxmd.com/read/28416835/-polymethylmethacrylate-augmentation-of-bone-cement-injectable-cannulated-pedicle-screws-was-used-to-treat-degenerative-lumbar-scoliosis-with-osteoporosis
#20
H L Sun, C D Li, X W Li, X D Yi, H Liu, H L Lu, H Li, Z R Yu, Y Wang
OBJECTIVE: To describe the application of polymethylmethacrylate (PMMA) augmentation of cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar scoliosis with osteoporosis. METHODS: Retrospective cohort study was used to compare cement injectable cannulated pedicle screws (CICPs) group with PMMA augmentation and control group with traditional method in the correction surgery for Lenke-silva level III and level IV degenerative scoliosis cases with osteoporosis...
April 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
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