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Natta Wiriyakun, Duangjai Nacapricha, Rattikan Chantiwas
This work presents a simple hot embossing method with a shrinking procedure to produce cross-shape microchannels on poly(methyl methacrylate) (PMMA) substrate for the fabrication of an electrophoresis chip. The proposed method employed a simple two-step hot embossing technique, carried out consecutively on the same piece of substrate to make the crossing channels. Studies of embossing conditions, i.e. temperature, pressure and time, were carried out to investigate their effects on the dimension of the microchannels...
December 1, 2016: Talanta
Masateru Nagae, Yasuo Mikami, Kentaro Mizuno, Tomohisa Harada, Takumi Ikeda, Hitoshi Tonomura, Ryota Takatori, Hiroyoshi Fujiwara, Toshikazu Kubo
INTRODUCTION: Polymethylmethacrylate (PMMA) cement is useful for spinal reconstruction, but can cause complications including new vertebral fractures, neurological disorders and pulmonary embolism. We report a case in PMMA cement used for spinal reconstruction after tumor curettage dislodged and penetrated the gastrointestinal tract. DIAGNOSES: The patient was diagnosed with a retroperitoneal extragonadal germ cell tumor at age 27 years. After chemotherapy and tumor resection, the tumor remained...
October 2016: Medicine (Baltimore)
Margherita Zani, Cinzia Talamonti, Marta Bucciolini, Marco Marinelli, Gianluca Verona-Rinati, Pierluigi Bonomo, Fabiola Paiar, Stefania Pallotta
PURPOSE: Aim of this work is the assessment of build-up and superficial doses of different clinical Head&Neck plans delivered with Helical TomoTherapy (HT) (Accuray, Sunnyvale, CA). Depth dose profiles and superficial dose points were measured in order to evaluate the Treatment Planning System (TPS) capability of an accurate dose modeling in regions of disequilibrium. Geometries and scattering conditions were investigated, similar to the ones generally encountered in clinical treatments...
October 15, 2016: Physica Medica: PM
Xue Rui, Yannan Jin, Paul F FitzGerald, Mingye Wu, Adam M Alessio, Paul E Kinahan, Bruno De Man
Computed tomography (CT) has been used for a variety of applications, two of which include diagnostic imaging and attenuation correction for PET or SPECT imaging. Ideally, the x-ray tube spectrum should be optimized for the specific application to minimize the patient radiation dose while still providing the necessary information. In this study, we proposed a projection-based analytic approach for the analysis of contrast, noise, and bias. Dose normalized contrast to noise ratio (CNRD), inverse noise normalized by dose (IND) and bias are used as evaluation metrics to determine the optimal x-ray spectrum...
November 7, 2016: Physics in Medicine and Biology
H Wang, P J Lv, Y Wang, Y C Sun
OBJECTIVE: To quantitatively evaluate the assembly precision of fabricating complete denture by computer numerical control (CNC) in manufacturing dentition and baseplate separately plus adhesive molding. METHODS: The 3D surface data of a standard edentulous maxilla plaster cast model and the temporary base-plate were obtained using an Activity 880 3D scanner. The data (data1) of a complete denture were designed using a set of computer aided design (CAD) software developed by the research group of this study...
October 18, 2016: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
Junshan Liu, Licheng He, Liang Wang, Yuncheng Man, Luyi Huang, Zheng Xu, Dan Ge, Jingmin Li, Chong Liu, Liding Wang
Polymer metallization is extensively used in a variety of micro and nano system technologies. However, the deposited metal film exhibits poor adhesion to polymer substrates, which may cause difficulties in many applications. In this work, ultraviolet (UV)-ozone surface modification is for the first time put forward to enhance the adhesion between metal films and polymer substrates. The adhesion of sputtered Cu films on UV-ozone modified polymethylmethacrylate (PMMA) substrates is enhanced by a factor of 6, and that of Au films is improved by a factor of 10...
October 17, 2016: ACS Applied Materials & Interfaces
Canan Turgut, Godhuli Sinha, Jouko Lahtinen, Kai Nordlund, Mohammed Belmahi, Patrick Philipp
Quantitative analyses in secondary ion mass spectrometry (SIMS) become possible only if ionization processes are controlled. The Storing Matter technique has been developed to circumvent this so-called matrix effect, primarily for inorganic samples, but has also been extended to organic samples. For the latter, it has been applied to polystyrene in order to investigate the extent of damage in the polymer, its fragmentation during the sputter deposition process and the effect of the deposition process on the spectra taken by Time-of-Flight SIMS (ToF-SIMS)...
October 2016: Journal of Mass Spectrometry: JMS
Xian-Hua Wang, Qian Dong, Ling-Ling Ying, Shuai-Shuai Chi, Yao-Han Lan, Yan-Ping Huang, Zhao-Sheng Liu
In this study, a new molecularly imprinted polymer chiral stationary phase (MIP-CSP) was prepared utilizing molecular crowding agent for improvement the selective separation ability. S-amlodipine (S-AML), methacrylic acid (MAA), ethylene glycol dimethacrylate (EDMA), and polymethyl methacrylate (PMMA) were selected as template, functional monomer, cross-linker, and molecular crowding agent, respectively. The composition of formulas for MIP-CSP was optimized, and the permeability and structural feature of resultant MIP-CSP were characterized...
October 15, 2016: Analytical and Bioanalytical Chemistry
A Lourenço, N Wellock, R Thomas, M Homer, H Bouchard, T Kanai, N MacDougall, G Royle, H Palmans
Water-equivalent plastics are frequently used in dosimetry for experimental simplicity. This work evaluates the water-equivalence of novel water-equivalent plastics specifically designed for light-ion beams, as well as commercially available plastics in a clinical high-energy carbon-ion beam. A plastic- to-water conversion factor [Formula: see text] was established to derive absorbed dose to water in a water phantom from ionization chamber readings performed in a plastic phantom. Three trial plastic materials with varying atomic compositions were produced and experimentally characterized in a high-energy carbon-ion beam...
October 14, 2016: Physics in Medicine and Biology
Luke J Higgins, Cristian A Marocico, Vasilios D Karanikolas, Alan P Bell, John J Gough, Graham P Murphy, Peter J Parbrook, A Louise Bradley
A range of seven different Ag plasmonic arrays formed using nanostructures of varying shape, size and gap were fabricated using helium-ion lithography (HIL) on an InGaN/GaN quantum well (QW) substrate. The influence of the array geometry on plasmon-enhanced Förster resonance energy transfer (FRET) from a single InGaN QW to a ∼80 nm layer of CdSe/ZnS quantum dots (QDs) embedded in a poly(methyl methacrylate) (PMMA) matrix is investigated. It is shown that the energy transfer efficiency is strongly dependent on the array properties and an efficiency of ∼51% is observed for a nanoring array...
October 14, 2016: Nanoscale
J Pauchot, A-P Sergent, G Leclerc, I Pluvy, L Obert
The induced membrane technique is used for bone reconstruction. It is based on the osteoinductive properties of a membrane induced by the insertion of a PMMA cement spacer. We will describe a simple, cost-effective method in which the body of a syringe is used to facilitate the cement introduction, allow insertion of a regular spacer, contain the cement volume in the extension of the diaphysis and protect the underlying tissues from the exothermic reaction during PMMA polymerisation.
June 2016: Hand Surgery and Rehabilitation
Erich Hellemann, Rubens R Teles, Fernando Hallwass, W Barros, Armando Navarro-Vázquez, Roberto R Gil
Anisotropic NMR parameters, such as residual dipolar couplings (RDCs), residual chemical shift anisotropies (RCSAs) and residual quadrupolar couplings (RQCs or ΔνQ ), appear in solution-state NMR when the molecules under study are subjected to a degree of order. The tunable alignment by reversible compression/relaxation of gels (PMMA and p-HEMA) is an easy, user-friendly, and very affordable method to measure them. When using this method, a fraction of isotropic NMR signals is observed in the NMR spectra, even at a maximum degree of compression...
October 14, 2016: Chemistry: a European Journal
Jae Ho Jeon, Sahng-Kyoon Jerng, Kamran Akbar, Seung-Hyun Chun
The deposition of thin and uniform dielectric film on graphene is an important step for electronic applications. Here, we tackled this problem by combining a simple chemical treatment of graphene surface and a modification of standard atomic layer deposition (ALD). Instead of common approaches trying to convert hydrophobic graphene surface into hydrophilic one, we took the opposite way by applying a self-assembled-monolayer, hexamethyldisilazane (HMDS) to make defect-independent, more hydrophobic surface condition...
October 13, 2016: ACS Applied Materials & Interfaces
Jonathan Watté, Wouter Tony Mathias Van Gompel, Petra Leona Lommens, Klaartje De Buysser, Isabel Van Driessche
A method to obtain photocatalytically active thin films of anatase nanocrystals on polymer substrates was explored. Anatase nanocrystals were synthesized by a fast hydrolysis synthesis in an apolar solvent and characterized with regard to their crystallinity, size, dispersibility and stability of the resulting suspensions. The stable titania nanocrystal suspensions were further processed for their use in polar solvents using ligand exchange. Oleic acid was exchanged for 3-aminopropyltriethoxysilane (APTES), resulting in aqueous suspensions of charge-stabilized nanocrystals...
October 13, 2016: ACS Applied Materials & Interfaces
D Espa, L Pilia, L Marchiò, F Artizzu, G Di Carlo, D Marinotto, A Serpe, F Tessore, P Deplano
A film of [Pd(R2pipdt)(dmit)] (1), where R2pipdt = 1,4-didodecyl-piperazine-2,3-dithione (acceptor) and dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate (donor) incorporated into a polymethylmethacrylate (PMMA) matrix, showing a good second-harmonic generation, has been prepared for the first time in the class of dithione-dithiolate 2nd order NLO-chromophores. Moreover full characterization of 1, including molecular second-order NLO properties in solution, is reported.
October 13, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Pin-Chuan Chen, Chih-Chun Chen, Kung-Chia Young
In this study, we developed a fully thermoplastic microfiltration chip for the separation of blood plasma from human blood. Spiral microchannels were manufactured on a PMMA substrate using a micromilling machine, and a commercial polycarbonate membrane was bonded between two thermoplastic substrates. To achieve an excellent bonding between the commercial membrane and the thermoplastic substrates, we used a two-step injection and curing procedure of UV adhesive into a ring-shaped structure around the microchannel to efficiently prevent leakage during blood filtration...
September 2016: Biomicrofluidics
Ayşegül Köroğlu, Onur Şahin, Doğu Ömür Dede, Şule Tuğba Deniz, Nurdan Karacan Sever, Serkan Özkan
This study investigated the effect of denture cleansers on the surface roughness and Candida albicans adherence of surface sealant agent coupled denture base resins. One hundred and twenty specimens were fabricated from 2 polymethyl methacrylate (PMMA) (Meliodent; Acron MC) and 1 polyamide (Deflex) denture base materials, coated with a sealant agent (Palaseal) and divided into 4 groups (n=10) according to overnight cleaning procedures: distilled water (control), 5% sodium hypochlorite (NaOCl) and two different sodium perborate (Corega; Rapident)...
2016: Dental Materials Journal
Atsushi Watanabe, Jiro Kumaki
Precise morphology control of ultrathin films is one of the important issues in nanotechnology. To this end, we describe that various controlled morphologies of hierarchical phase separation can be attained using poly(methyl methacrylate)-b-poly(n-butyl acrylate) (PMMA-b-PBA) monolayers spread on a water surface. At a low surface pressure, they were miscible, but upon compression, phase separated with a monolayer of the major component block spreading on the water surface, on top of which the minor component block separated out (hierarchical phase separation)...
October 4, 2016: Journal of Colloid and Interface Science
Yu Lin, Langping Liu, Dongge Zhang, Yuanbiao Liu, Aiguo Guan, Guozhang Wu
Establishing the relationship between interfacial layer chain packing and dynamics remains a continuing challenge in polymer nanocomposites (PNCs). This issue is expected to be significant in our understanding of the mechanism of the dynamic response of such materials and the manner in which these parameters affect the macroscopic properties of PNCs. In this study, we report the dynamics of free polystyrene (PS) and poly(methyl methacrylate) (PMMA) matrix chains, as well as those of polymer chains surrounding the spherical silica nanoparticles (NPs) where silica NPs are either bare or PS grafted, to discriminate the role of grafted chains and interfacial interactions between grafted NPs and the matrix...
September 27, 2016: Soft Matter
Solen Cubukcu, Haluk Yücel
In this study, paraffin was selected as a base material and mixed with different amounts of CaSO4·2H2O and H3BO3 compounds in order to mimic breast tissue. Slab phantoms were produced with suitable mixture ratios of the additives in the melted paraffin. Subsequently, these were characterized in terms of first half-value layer (HVL) in the mammographic X-ray range using a pulse-height spectroscopic analysis with a CdTe detector. Irradiations were performed in the energy range of 23-35 kVp under broad beam conditions from Mo/Mo and Mo/Rh target/filter combinations...
October 7, 2016: Australasian Physical & Engineering Sciences in Medicine
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